Dome Light Mod to Trigger Other Lights

In my ceiling electrical rough-in post (See here), I described the ceiling wiring. Among the circuits, I mentioned the original dome light, and moving it over the slider. I wanted to take this 3-position switched light and have it optionally trigger the dome lights in the rear and the front. Today's post will cover how I made that work.

Original Dome Light

dome switch innards

Let's start with a review of the original light and switch. This switch is some basic stuff. There are 2 wire tabs near the switch and one at the other end of the housing for connecting to ground. The 2 tabs correlate to the wire that connects to the switch on the dash (if you still have it) and the switches in the doors (again, if you still have them). The door switched side of my dome light never worked, and I removed the switch from my dash so I could reuse the hole for the heater fan switch. But, I digress; there are 2 tabs. The tabs relate to either side of the 3-position switch, with the middle position for all-off.

Inside the light housing, how the switch works is more apparent. Each wiring tab has a corresponding little tang that hangs or runs down towards the lens on either side of the plastic switch. Outside of each tang runs a metal arm that connects to the positive side of the bulb. So, when the plastic switch is moved from the middle / all-off position, it pushes the little tang against the metal arm, closing the circuit. When 12V is sent to the corresponding tab, the bulb lights up.

Experimenting

So, with that context, we consider how do we tie into the switch to close a circuit elsewhere. The wiring to the other bulbs has been strung; they just need 12V sent when the switch is flipped. We cannot just attach to the metal arm, because then the remote lights would fire up regardless of which position the switch was in. If that's your goal, then that's great, and less difficult. We cannot just tie into the wiring tab because then the remote lights would be on all the time. We need to somehow tie into the movement of the switch so that when the tang is pressed outward, we can pick it up for the extra lights.

experimenting

I noticed that the little hang-down tangs are not the same length, the amount of exposed brass related to each circuit is not equal and the wiring tabs are 90* offset from each other. I do not know how much these details relate to one another, but the longer length of the one hang-down tang provide a way to tie in. The longer one is attached to the side with less exposed brass overall and with a wiring tab that is parallel with the lens. Again, not terribly relevant.

I conducted some experiments with the switch and a bare-metal female wire connector (picture on the right), as opposed to one that's wrapped with a plastic housing. I was able to set a connector fairly close to the housing, but not touching any brass, unless the switch was moved in that direction. Then, the female connector would make contact with the end of the hang-down tang. It was a great fit inside the lens, and did not prevent the circuit connecting with the metal arm. Similar experiments with a wire connector that had a plastic housing produced different results: did not work. The housing was too thick to fit in the space, even if I cut it down so there was metal exposed for the tang. I tested connectivity with a basic multi-meter to confirm that the switch would create a connection when engaged in the one position, but not at any other point.

After spending the better part of a weekend morning fiddling with this plan, I had to change it. I glued the female wire connector onto the lens and discovered that during the experiments, the connector moved slightly as I activated the switch. So, when I had it completely stationary, it jutted out just enough to prevent the tang from touching the arm: the connectivity on the multi-meter was infinite. So, that bulb would not power up had I left it that way. The lesson here, I guess, was to vice-grip the female wire connector in-place during the experiments so it would absolutely not move.

Tying In

bailing wire tang

So, I considered something that was smaller, and more like the little tang I was trying to interact with: a short stretch of bailing wire. With the tip of my needle-nose pliers, I shaped a hook-end and then a twist to create a footing I could adhere to the lens. Learning from my experimenting mistake, I set the bailing wire tang in place with vice-grips and repeated my experiments. In retrospect, something more pliable for the tang, like some thin copper or even a short stretch of solid 20ga wire probably would have been more effective because it would have more flex/give when the switch was flipped. Still, after a few cycles of set-test-reset-retest, I was able to find the spot when both the original arm and the new bit of bailing wire demonstrated connectivity with the wiring tab when the switch was in position.

I soldiered a stretch of insulated 18ga wire to the bailing wire tang, and then a-fixed the tang to the lens with superglue. Once the glue set up, I repeated my experiments to make sure that I could consistently find connectivity from the wiring tab to the end of the 18ga wire as well as the on the original light.

Triggered

Reasonably or not, I considered the amp draw through that little connection between the tang and the bailing wire, and assumed that expecting 2 lights to get powered through it is asking too much. So, to protect against overheating that connection, I'm adding a basic 4-pin relay. Recall the basics of a relay: when there is a sufficient voltage difference between pins 85 and 86, a connection is made between pins 30 and 87. So, we connect the inbound juice (that will be attached to the tab on the light) to pin 30 and ground pin 85. Pin 87 connects to the wires supporting the remote lights and pin 86 connects to the bailing wire tang I added to the light fixture. Because of where I am putting the light over the slider, there is considerable room in the ceiling for the relay and the extra wire.

Install Awaits

one switch. 3 lights

Parts of this could be installed immediately, but so much of the interior is still in disarray. The sound suppression steps are still ongoing, the remote lights are still just bare wires. I thought about stuffing the relay up into the ceiling, but decided that I could just as well wait and install the whole unit at once. Before setting it aside, I confirmed the concept, though. I pulled out a car battery, and set the 3 light fixtures on my kitchen table. I ran wiring between all the lights, and the relay, and simply played with the switches (note the fuse next on the positive side of the battery on the right edge of the picture). Yes, I did use clothespins to hold the wires together; I didn't want to stress the wires by twisting them together or waste wire connectors. When the original dome light is in one position, all 3 lights fire. When it is in the other position only that light comes on. Perfection. While I had it all set up, I played with the other (remote) lights, just cuz. I will, of course, have to retest everything when it gets installed, but seeing things light-up gives me some confidence that the concept, and maybe even the implementation, will work.

That's it for today. Thanks, as always, for following along-

Oh, Nemo

Today's post covers my challenges with Nemo's electrical and computer system simply trying to get him to start, or maybe a signal on the OBD-2 port. The car-work hours that I did not want to spend sanding on Zed, I spent doing this... until this took over. Yeah, I know. I could use another hobby.

No Start

Like so many issues with these old cars, our challenges with Nemo started with him not starting. His battery had been sitting on a trickle charger all winter, but I had left his hood cracked to make room for the alligator clips, so this ultimately was self-inflicted. Love those. But, the path we took to get there was interesting. Nemo is sitting under the fabric carport blocking a garage door. Behind that garage door sits Oliver, the 1978 MGB convertible, that I would very much like to be road testing and otherwise driving around. So, enter my motivation for moving Nemo. Insert key, turn ignition to "RUN". I see some familiar idiot lights, including the battery, oil and check-engine. Turn to "START" and he rev'd but would not start. I went around to the tailpipe and could not smell gas, so I start with the assumption that it is fuel delivery.

Before I did anything else, I considered what I experienced when I turned the key to "RUN". I did not hear the fuel pump cycle. I did not hear the radiator fans kick on. So, something is not getting the "RUN" signal. So, I pull out the UltraGauge and plug it into the OBD-2 port. I get a never-ending "scanning..." message. Well, that's not good. I double-checked the UltraGauge in Hapy, and the computer linked within a few seconds. Okay, we have trouble with Nemo's diagnostic system which could prevent a start or we have multiple things going on. With this car, the latter is probably true. First, I tried to isolate the OBD-2 issue, and kill many many hours doing so.

OBD-2 Issue Diagnosis: General

The early B5 versions of the A4 had some interesting 1 or 2 year only issues. One of the oddities around 1997, when Nemo was sold, was the engineers choice to integrate the stock stereo with the "K-line": the signal processing wiring between the computer, many components and the OBD-2 plug. In these late 90's cars, it is the K-line you are subscribing to, not the more modern "CAN BUS". Okay, cool. There are many modules plugged into the K-line, but they are all in parallel. the diagnosis theory goes that when you get no signal on the K-line it is because one of the modules is faulting out, grounding the K-line. Once you can identify and remove the faulty module, you will get a signal on the K-line. You will probably get a failure code for that module, but you will at least get a signal. So, away we go, trying to figure out what modules are even on the K-line, and then isolating them.

OBD-2 Issue Diagnosis: Radio

The stock radio wiring was unceremoniously cut to pieces by the idiots at Car Toys when they installed an aftermarket stereo. Based on the wiring diagrams I have found and the commentary on the interwebs, I am not sure this car actually had that K-line-in-the-stereo thing. I did check the wires for the right color combinations, and for wires that were the correct colors for the K-line. I was unable to find them. There are, however, many wires sticking out of the hole where the radio used to be... before it was ripped off in Eugene. I intend to re-integrate an original plug before I put all this back together, but that's another day. I moved on to the next possible culprit: the climate control system.

OBD-2 Issue Diagnosis: Climate Control

found in climate
computer

The climate control system in these cars is another little computer. In some models, it is held in place with a couple brass clips. In Nemo, I had to remove the center console cover plate / face and found 2 Phillips screws holding it in. Once threaded out, the unit removes through the front. I unplugged the unit and checked the OBD-2 for a signal. Nope. I did, however, find a soda/beer can pull tab inside it (picture on the right, here, laying on the carpet after I removed it from inside the climate control computer thing). So, that was interesting. Next.

OBD-2 Issue Diagnosis: ABS (Brakes)

The fine folks on the interwebs have found that the ABS sometimes causes K-Line problems. The way to identify if it is the problem is to disconnect the plug. The ABS unit is on the driver (left) side, next to the washer bottle. You simply pull up on the silver metal tab and the plug lifts out of the socket. I found a piece of electrical tape floating around in there. Another question-mark from the prior owner. Neat. I checked the OBD-2 for a signal. Nope. I shot the socket and the plug with DeOxit and left it disconnected for the rest of my tests. I figured I might as well leave it better than it was (DeOxit, not leaving it unplugged). Next!

OBD-2 Issue Diagnosis: Dash Cluster

Moving on, we consider the dash cluster. The entire thing is held in by 2 Torx-head screws from the front, hidden behind a cover plate just above the steering wheel. Pull the cover plate, remove the screws and it pops right out. I unplugged the various cable plugs and checked the OBD-2 again. Nope. Grr... Next!!

OBD-2 Issue Diagnosis: ECU

example A4 ECU 

It seems like every system on the engine that has more than one wire into it delivers some signal to the computer. So, this seemed like the next logical step. I figured if I could get a signal after unplugging the small plug on the ECU, I would have shown that the issue is in the engine compartment and I could put everything in the cabin back together again. If the issue remains, then it could be the ECU. So, I disconnected the small plug from the ECU and we still didn't have a K-line signal. Grr...

So, I plugged the ECU, ABS and the dash cluster back in, turned the key to RUN and heard the click-snap of some relays firing, but no fuel pump nor fan spin. I could not remember if I heard the relays before, but this changed my thinking. If at least some of the relays are firing, then the ECU is telling them to. If there is a Check Engine Light, then the ECU must be at least partially working. Perhaps the K-line / OBD-2 issue is completely unrelated and this is just a simple fuel supply issue. So.. new plan: get the fuel pump to fire.

Fuel Pump Test

As is so often the case in laboratory settings, the pre-work for the experiment is where all the time is taken. Such is the case here. I started by removing the plate covering the fuel pump. This sits behind the rear seat in the trunk on the passenger (right) side, and is held in place with 3 very short Phillips screws. Once the plate is removed, you can see the top of the fuel pump. There are 2 fuel lines, one supply and one return, and a single electric plug. I found that slightly wiggling the plug allowed it to pull off the pump. YMMV. Once removed, you will see 4 pins. 2 of them are for the fuel level and 2 are for the pump. I started my tests with basic resistance and continuity-to-ground. Things seemed fine, so I shifted focus to test-firing the pump by applying 12V to the pump.

This is where the experiment set up took some time relative to the actual test execution. I ran a pair of wires from near the battery (not hooked up) back to the fuel pump. At the battery, I taped 10A fuse to the "red" wire and alligator-clipped the other side of the blade to the positive battery post. I alligator-clipped the "black" wire to the negative post. Back at the fuel pump, I applied the red and black wires to the fuel pump and it fired right up. I held the wires there a few second to demonstrate that it would not just run for a second and die. So, we have a good pump, but the pump won't fire from a relay signal. So, next we check the voltage from the relay, after we put the experiment wiring away.

Fuel Pump Relay Test

A4 Fuel Pump Relay

Back up front, I took a red wire, stuck it into the voltage-supply pin in the wiring plug at the fuel pump and tossed the other end through the cabin, over the outer edge of the driver seat. My plan was to compare the voltage sent to the pump at the pump. Since the relay only pops for a second when you turn on the ignition, I had to have my test equipment near the ignition key. I stuck my black lead against the metal fuse box mount, held the red lead against the wire I tossed through and turned the ignition to "RUN". I got 5V. I checked other spots around the fuse box and got 13V, so I started thinking that the relay was bad, dropping the voltage from 12/13V to 5V which, of course, is not enough to run the pump. So, I swapped out the relay... and the fuel pump still would not run. Great. I concluded that the 5V I read was actually the base charge for the fuel level sender and not the supply for running the pump. 

So, I checked the voltage at the supply-side of the relay: 13V. I jumpered across the relay pins, and the pump fired up. So, we're back to the ECU is not sending a signal. Fearing it is the ECU, I went looking for any other reason. I recalled that when Dot (the white 2000 VW Jetta 2.0 which broke the timing belt) failed, one of the theories for not starting was a crank position sensor. The thinking is that if the ECU doesn't know where in the revolution the crank is, it doesn't know when to fire, so it doesn't try. It is not as clear whether a failing crank sensor would prevent the fuel pump relay from getting a signal from the ECU, however. As much as I have tried to avoid it, it felt like I was sliding into just-swap-parts problem solving. At $35US for the least expensive part-to-swap (crank position sensors start closer to $60US), this can get needlessly expensive very quickly.

Crank Position Sensor (CKP)

A4 Crank Position Sensor

I have mentioned before my belief that the Audi engineers are sadists. Only someone who takes pleasure in other's pain could arrange for replacement items to be so hard to get to. Case-in-point: the crank position sensor. The crank runs the length of the block (obviously), so given a blank canvas, an engineer could potentially place a sensor anywhere along that axis. Chosen location? Directly under/behind the oil filter so you either have to remove the oil filter (forcing an oil change, which arguably is due) OR you need to perform contortions to get an Allen-head wrench in there. If you go this route, consider that the further the bolt comes out, the closer you get to the oil filter. At least there is only one fastener. These sensors have a long lead on them that plugs into the engine harness... behind the coolant bottle. In Nemo's case, this plug was fairly easy to get to. There are methods for testing the sensor, of course.

The Audi/VW sensor has 3 wires, from pin 1-3: power | signal | ground where the power and signal connect to the ECU and the ground finds its way to the chassis. To test, 12V and ground need to be supplied to the sensor plug (once disconnected from the harness) and a multimeter checking the signal wire for an AC wave signal while the engine is turning. No signal = bad sensor. Since no local shops had a CKP, I returned to sanding Bondo in Zed while I waited for the part to arrive.

Once I had the part in hand, I checked the resistance between the pins. I got 500ohms +/- between the middle pin and one of the outer pins. Using that as a baseline, I swapped out the CKP and then tested the one I had just removed. Same resistance. So, I concluded there was nothing wrong with the old one and put it in the stash of A4 spare parts (with the fuel pump relay).

ECU Swap

At this point, I had run completely out of ideas fo4r why the ECU was not sending a "go" signal to the fuel pump relay. I hit the local junkyard looking for a just-dropped-off A4 to scavenge the ECU. None of the A4's there had the right ECU, but I did get an ECU box cover: Nemo's had a good-sized hole in it where I thought water might have entered. Without another option, I hit eBarf and found an ECU with the same part number as the one as was currently in Nemo at a salvage yard on the East Coast (with a 30 day return policy!). Hopeful, I swapped out the ECU's which consisted of pulling out the big plugs in the back of the old and plugging them into the new one, since the box was still lid-less. I had some concern that energizing the ECU could fry it if the underlying condition still existed.

Still, I turned the key to "RUN" anyway... and heard the radiator fans and fuel pump cycle for a second before shutting off. This was how things used to work. So, I turned to start and he fired right up. I have concluded that my first guess was the correct one: I had left the hood open a little bit to make room for the alligator clips on the trickle charger, and with the hole in the ECU box lid, water got into the ECU and partly fried it. If I had not had the experience with the chipped ECU for Hapy when the computer semi-worked, I would not have been so quick to accept this. The Check Engine Light lit, so the A4 chat-boards all assume that means the ECU is fine. NOT TRUE. It could be partly damaged, like Nemo's.

The climate control is still in pieces, the lower dash panel is off, and the radio wiring, well, it's the same as it was: a mess. While I can move Nemo out of the way so Oliver can go for a spin, Nemo is not ready for driving around just yet. The re-assembly will wait, and I'll probably post on at least the re-wiring of the stereo plugs that the idiots at CarToys cut apart. I did, however, install the ECU box lid, complete with threading in the screws to hold it tightly shut. No more water getting in there.

Thanks, as always, for following along-

Hapy Daily Driving

Well, that title might be overstating it a little bit. To clarify: Hapy is now capable of driving on a moment's notice. With the CoViD safer-at-home, I haven't been going anywhere. I may not have had an operable car for most of the last couple of months, but the lockdown has meant I haven't really needed one either. Today, I'll cover the little things that needed to be buttoned up after the big re-wire.

Reverse Lights

I mentioned the reverse lights at the end of the Electrical Gremlins saga. I had it wired up to a somewhat mystery switched 12V source before. When I tore the old wiring rats nest apart, it was left out of the new wiring. This resolution was fairly easy. Back when I set the mystery wire-up aside, I left the plastic-snap-shut fused wire in tact. So, there was just a plain bare wire to deal with. I fished it up into the spare tire well / wiring compartment from the engine bay. I spliced the wire into the switched source splice coming from relay 109 so the reverse lights will only come on when the computer thinks we are in "RUN". Since it already had an integrated fuse, this was a simple splice effort.

Headlight Flasher

When I was chasing the cause for my lack of amps during P0121 testing, I tore into the dash. I thought I had bumped something loose, and there are a bunch of things in there that could have shaken apart. Well, I didn't bump anything loose causing that issue, but I did bump something during that exploratory. Haha. During the Summer of 2020, I finally got my high-beam / low-beam flasher relay to work. It was because the replacement relay requires a source of 12V to pin 30. This pin wasn't on the old relay, and there is no wire leading to that pin in the original fuse box. I solved that before, but when I was looking for the buzzing noise during the P0121 effort, I pulled that relay and the wire heading to that pin fell out of the fuse box. I didn't notice that then. During post-testing, I discovered that the flasher no longer flashed. I found the wire, re-oriented it so it would not fall out, and returned things back to their prior cleaned-up state (zip-tied fuse-box). Hi-beam flash/relay works.

Defroster

Also in the Summer of 2020, I installed a defroster. Sort of. The defroster solution was moving the Vanagon rear heater under the belly, routing coolant along the driver side main beam and plumbing into the old air channel from just behind the front crossbeam. The air source was an experiment pulling from the old rear floor vent. The mechanical connection of the hoses to the heater was poor, and the experiment fell apart. This source needed to be remedied. Also, the switch was not operating the fan settings correctly. This was caused by poor quality wire connectors, so once the 3 at the switch and the 2 near the heater were replaced, we have a 3 speed fan again.

I decided that rather than solve for a cabin-source of air for the defroster, I would just remove the experiment for now. I have an idea for a source, but other cars need my focus. So, I removed the air supply hoses and called it good enough for now.

Mop Up

During all of the wiring work, the inside of the bus became considerably disheveled. It was one part shed, one part tool box and no part looking like a vehicle. This was easy to resolve, but made a huge difference in declaring the end of the work. The lot couch is back installed as a middle-row bench seat, for example. The rear speakers are hooked up and placed for sound again. After a quick trip with the shop-vac to get the wire-strippings and other fallout from all the work vacuumed up, he looked nearly ready.

I ran a test of the furnace, confirming that it would run on either the accessory battery or the main. It will, but the current draw for the glow-plug is so significant that I'm not sure I will want to start that heater if I am not running at least a float charger to the sourcing battery. Still, it moved the internal temperature of the bus from 43*F to 68*F (6*C to 20*C) in about 15 minutes. For the fuel-minded, it took about 500ml (or ~0.13US gallons or about 2 cups). As I understand it, maintaining the temperature requires far less fuel, so the consumption at that point dropped way off. I left it running for about an hour and the total consumed ml was about 530ml or 30ml (1/8 cup) for the remaining 45 minutes of keeping the bus warm.

I took one last step: I installed plastic kick panels I ordered like a year ago against the rear of the nose of the bus. Just like that, the cab looks like it is not an active project. It looks fairly clean now, actually. They install and remove easily, and once snapped in they really do not appear to need much more to hold them in place. The guy who makes them suggests poking holes through and screwing them into your bus. I might use Velcro, but I'll withhold decision-making until after we have had a few drives to see if they rattle or not.

Getting Legal

This last thing was actually one of the first things I did for Hapy after I set Zed aside. In fact, I think it was the registration that got me thinking about Hapy in the first place. His registration came due, and because of CoViD-19, I had to do it remotely. Since he is too old for smog and Oregon does not have inspections, I have been renewing his registration online for a few years. Still, this time I did the online steps in October 2020, but did not receive the stickers for his tag until January 2021. This used to take a couple of weeks at most. It sure felt good getting those stickers on his plates, though.

Test Drive

With the tags updated, the wiring fresh, the defroster responding, furnace functioning, etc... Hapy appeared nearly ready to be pressed into service. We just needed a test drive. For that, I did my usual neighborhood lap through a series of side streets out to the main drag, a quick 1-mile straight shot on that major street and then turning back into the side streets for home. As expected, Hapy was fairly peppy and responsive. He sounds great, and did not suffer any P0121 issues. There were a few stutters, but no codes, so I chalked that up to old diesel. That will solve with some snake oil and a fill-up. Considering that Hapy had not left the driveway in over a year, this drive was significant, albeit short.

Alt-Light

The battery light came on when the engine was revving low during the test drive, leading me to think that the unsettling "pop" noise I heard when the wiring was wrong (See Chasing the Hapy Electrical Gremlins - Part 6) was the sound of my alternator frying. This light had been popping on during testing, so the fact that it returned during the road-test honestly just reminded me. Before I jumped into anything, I in-bus tested the alternator: I alligator-clipped a fused wire to the alternator output and ran that wire on the ground up to the cab. There, I electrical-taped the bare wire to the positive probe of my multi-meter to free a hand. I set the negative probe into a small bolt-hole in the driver door frame for a good ground. First, a good base reading: 13.5V. Cool. I started the engine and it dropped down to 12.4V. Solid. With my hand on the go pedal, I revved the engine and watched the voltage climb up and down peaking above 14V. So, the alternator is fine. Since I have been running without an ALT/GEN light for 10 years, I could just ignore that light... Nah, I just can't do that. I figured that the bulb must simply be connected to the wrong wire of the 2 in the ALT plug.

I had spliced into the wire heading to the computer (DFM - or Digital Field Monitoring), and it needs to hit the one that routes to the cluster (L - Lamp). Simple fix: I cut the splice from the donor main harness to the 6-wire cable, and tied it into the other wire from the plug just upstream from the 4-pin plug. While I was back there, I added ring terminals to the sensor wires for the oil pressure and oil idiot light. There remains some wiring tidying I need to do on the driver's side, so I'll cut out the rest of the DFM-sourcing wire when I'm in there. 

As much as I'd like to say that once I completed, I took another test drive... I can't. I did test start and engine-rev in-place, however, just to see that ALT light wink out (which it did). Why did I not drive him? Well, remember Gramps (1996 VW Jetta 2-dot-slow from my folks that we gave to K2)? He re-appeared with a failed throw-out bearing after the first test drive, but before I'd solved the ALT light. So, I will have to juggle the herd to get Hapy free for a drive. And, you can probably guess what I'll be working on next.

That's it for today. While I may not need to go out much due to CoViD restrictions, I now have my beloved turbo-diesel powered microbus available-ish for whenever the need arises. While there are lots of little things I could tweak on Hapy, none of those things would prevent me from taking a drive. Sweet, sweet success. Thanks, as always, for following along.

Chasing the Hapy Electrical Gremlins (final)

Well, it may have taken a while, but with today's post, we are done with the re-wire of the "fuse box harness". I did not mean for this to become such a large endeavor, but that's what happens when you lose focus for a few minutes and cut some wires too close to the fuse-box for you to re-integrate them. I was asleep at the switch and missed my usual release time, so it's a few hours later than usual this week. Hapy last day of the worst US presidency in modern history; may the transition to the new guy be a smooth reflection of 200+ years of our democracy in action.

I realize that for many readers, this series has not been terribly interesting. I get that. Electrical sucks. However, if you were thinking about doing a swap, I think this series helps demonstrate how much of the swap work is done with a multi-meter, and how little is done with a shop-crane / engine hoist (or a floor jack).

Today, I will go over my steps to determine what went wrong in my system test in part 5. Apologies for no pictures of my testing. I'm not sure what would have been picture-worthy, except, maybe, my "fused wire", but that's not terribly interesting, I don't think. I mean, it's just 2 wires, each with a male wire connector on one end (to plug into relay sockets) and a female connector on the other. The two wires are then joined with a bladed fuse plugged into the female connectors on the 2 wires. So: male connector - wire - female connector - bladed fuse - female connector - wire - male connector. Easy peasy.

The T-12

Before I get into it, I realized after posting part 6 that I put a picture from when I was integrating the T12 wires into the front-to-back cable, but I didn't give any context nor explanation. That picture was illustrating that once I cut the cable, it wanted to spring back through the engine compartment and over the driver-side axle. Resisting that spring-effect does not help one make solid wire connections. So, I held the cable in-place with a vice-grip. Some of the ShadeTree solutions are just funny enough to be photographed.

Isolate

I mentioned in part 6 that I removed the diode between the RUN and START relays. This isolated those 2 circuits. I continued down this path by pulling all of the relays and fuses from the new fuse box, disconnecting the two always hot (30) circuits from the battery-top fuse box, unplugging the "D plug" from the alternator and removing the connection to the reverse switch. So, now, the engine and new fuse box are completely isolated. My plan to find the issue is from here, we slowly add things back in, testing each planned connection first.

Original Bus Loom

I started with the main bus. This wasn't touched, but still, if we can eliminate that huge variable, so much the better. So, I turned the key to run, flipped on the running lights and then the headlights. I even flashed the high-beams. Everything was working great at this point, but nothing in the old loom was changed. I did discover that one of the grounds on the front (front-is-front) of the dash was falling off, so I tightened the connector with some needle-nose pliers and kept moving. I felt confident that the test I had just done was not going to trigger a battery discharge. I did not have that feeling for anything I spent weeks modifying, so the rest of the tests below were much more careful. The next step is re-integrating the donor stuff.

New Fuse / Relay Box

My process was pretty much the same for evaluating and connecting the donor stuff and new fuse box: Identify the circuit, and before you connect it, check the amp draw. Pretty much, regardless of the reading, I then tested the connection by bridging the gap with a fused wire. I would select a fuse that was appropriate for the circuit being tested. In the case of the red always-hot wire going to the new fuse box (relays 109, RUN and START), I used a 20A fuse, and it didn't pop. To be fair, this test really only proved that this red wire was not itself going to ground independently of the key going to "run"... which wasn't happening. And, the relays were all pulled when I did this. So, this test was not as meaningful as I thought it was when I did it. I connected the circuit and verified voltage at the relay 109 socket 30,  before moving on.

Once I had the main power to the 109 relay, I popped it in place and the tested the RUN relay socket. Similar to the process I described above, I checked the amp draw between pin sockets 30 and 87. Then, I made the connection between them with a (20A) fused wire. Once validated, I only put the relay in once to confirm that turning the ignition key caused the same behavior. It did. After that, I did not plug in the relay simply because the ignition key is 15 feet away from this fuse box, and I just did not want to have to keep going out from under the carport into the pouring rain. Besides, this kept the testing isolated, as I continued to trigger RUN tests with a fused wire jumping from 30 to 87 in the RUN socket for the rest of the fuse box tests. I validated that socket 30 of the START relay socket was present. Yep yep.

I repeated this testing process with each of fuses 1-3 (11/15, 12 and 29 respectively) in the new fuse box, and then the connection with relay 109 before inserting relay 109. In each case, the steps were to check the amp draw first, then insert the fuse. Next, I repeated that process with fuses 4-6 (32, 34 and 43 respectively). I had a moment where my relay 109 was humming during the investigation of fuses 4 or 6 (34 / 43) which I tracked down to my not having had two grounds (one for the ECU and one for the main harness) re-attached during testing. Now, after the fact, I think this could have been a big deal, but as I worked through these steps, it was not apparent.

At this point, I had all 6 of the fuses installed and the 109 relay. When I bridged across pin sockets 30 and 87 of the RUN relay, the dash-pod would illuminate, the odometer displayed and idiot lights would come on. After a few seconds, most of the idiot lights turned off. The glow-plug light flashed though, and I realized that I had not yet tested the glow plug relay. I repeated the process for the glow-plug relay (180) and last, plugged the relay in. Once power was applied via the RUN socket, everything was the same except the glow-plug light winked out with the others. I had not yet wired in the always-hot (30) for the glow plug, though, so that was next. Same amp draw and voltage check process, same result.

Front-to-Back Run Relay

I figured testing the RUN and START relays was next. First, I plugged in the alternator "D" plug and tested everything again. As before, everything was as it should be. As I worked through this stuff, I suspected it was one of 2 things: either it was related to the "other 2 relays" I haven't really documented -or- it was because of this plug, since I split this signal to the front of the bus. So, my next test (of the RUN) relay from the ignition switch would be done first without the "D plug" clicked in.

 

This test was rather simple: stuff a standard Bosch-style relay ( I re-used one of the "53's" from the donor) and turn the key to run up front. I had already done this once before so this should not have been dramatic, and it wasn't. The donor electronics did the same thing as before. Feeling confident, I figured that the starter circuit would be just as seamless. That was not the case, and it was here that we found our cause.

On a side note, the relays with a "53" stamped on them appear in a few places in the TDI relay panel, but they also appear in the little relay box for triggering the coolant glow plugs. So, I figure these should be up to the task of carrying some decent current. Not that either of these do that, but the RUN relay needs to be on so long as the key is on, so I would think that takes some stamina. Oddly, in the 10 years since I first did this, the old Radio Shack basic 12V automotive relay never failed me.

Starter Relay and Starter

I started this test like the others: test amp draw, bridge the 30 and 87 relay sockets with a fused wire and see what happens. The starter grunted like it was gonna try to start the engine, so I quickly pulled the wire and figured things were fine. I put another spare donor "53" relay in the socket and turned the key to RUN and then to START. This time, what happened was what happened during my full system test: a pop followed by everything going dark. Concerned that the starter was blown, and that was causing the problem, I pulled and tested the starter.

I have an old battery sitting on my garage floor for things like this. I ran a set of jumper cables from the battery (negative to starter mount tab, positive to positive post on the solenoid. Then, with my fused wire, I jumped from that positive post to the start trigger and the start fired right up. 

Since the starter tested fine, I slapped it back in. While I was on my back working the long mounting bolts back in, I remembered that I had split the START signal at the ignition just like I had split the RUN signal. At the time, I had not yet hosed the wiring in the donor fuse-box with my aggressive wire-cutting, so I was intending to keep the original starter trigger from the ignition, but to also send a start signal to the donor ignition switch wiring so the ECU knew when a start was being attempted. This all made sense at the time, though now in retrospect I realize that the ECU doesn't need to know you're starting. Later, after this effort mushroomed, I connected the starter signal to the T6 like the donor engine was triggered, and forgot about the old start signal wire. So, now that none of that old stuff is being retained, that old start signal was going somewhere... and possibly shorting us out. 

Start Trigger

I very much wanted to test this theory. First, I confirmed that I had not screwed up anything new: get the battery hooked back up, verify it's at 12V or higher and reset for the prior test with the RUN relay, etc. Turned the key, and we're looking at a code-free dash-pod again. Nice. I turned off the key, and cut the wire from the start side of the ignition key to the original bus starter wire, and reset the key to RUN. Back at the fuse-box, I tested the START relay and the engine tried to start. Hoping that we may have found our root cause, I went back up front and turned off the key.

Remember how I removed that diode between the RUN and START signals? I confirmed that the RUN side of the ignition switch continues to deliver 12V when the key moves to START at this point. I simply measured the voltage at RUN when I turned the key to START. Since the START position was now only sending 12V down to the relay socket, nothing happened. We did still have 12V at RUN, so the diode is not part of the new wiring.

Back at the bus rear, I replaced the donor "53" relay into the START relay slot, plugged the alternator "D" back in and returned to the front of the bus. I turned the key to RUN... all the usual lights lit up. I turned the key to START... and Hapy started. He sat idling while I danced around a little bit. I did notice, however, that the battery light on the donor dash-pod was still on. So was the light on the bus dash. So, while Hapy starts and idles, some issues remain. Okay, we'll figure that out... Also, after a few minutes, Hapy's idle increased from bouncing around 900 to... 1200 rpm firm.

Next!

Ugh, the dreaded 1200 limp mode is still around. I'll be working on that next, as well as hooking up the reverse lights, and looking into those other 2 accessory relays that apparently were not part of the problem. I have some documentation to mop up with regards to the diagram, so I'll be spending a few evenings getting that done too.

I will have different blog posts and titles for all of that stuff (may not post on the diagramming), since this was really about simplifying the wiring. You could argue that this "Electrical Gremlins" series started because I couldn't get Hapy to start with any consistency, and now I can. So, that's it for today. Thanks, as always, for following along-

Chasing the Hapy Electrical Gremlins (part 6)

Continuing the saga of fixing the front-to-back (or original bus to donor engine) wiring, today I will cover some of the bus install joy. Consider that the positive battery cable has been disconnected this whole time, and the battery has been on a float-charger. I strongly suggest that you do the same any time you are playing with your electrical system.

Make It Fit

how it looked before

When I left off last time, I had accidentally cut wires from the donor fusebox that I ideally would not have. This led to a complete re-do of the fuse-box wiring harness. After spending my holiday break addressing that harness, and test fitting, I was about ready to start installing it. I plastic-wrapped the clumps of wires, and took the whole thing out to Hapy. I spent a few minutes looking at how things would fit and it quickly became apparent that I could have shortened the wire-clump going to the oval T10 by a couple of feet. Oh well. I stuffed the T10's, the custom T12 and the collection of leftover wires down through the hole in the bottom of my spare tire well. I should probably point out that when I first did this conversion 10 years ago, I cut a larger hole down there, approximately 1 inch across by 2 inches front-to-back.

With the harness pretty much where it needed to be, I removed the dash pod from it's mount and plugged in the blue and green connectors. The dashpod set back into place, and was bolted back in quickly, like end-to-end in 15 minutes. Next, I plugged in the computer and pressed it into place on the plastic holder/stand. The ECU really didn't move much once I had it set in, which, when we consider the thickness of the cables heading into it, really doesn't surprise. I will be applying bungy-ties eventually to hold it in place. This left the fusebox. I test fit it to make sure the wiring lengths were good and then let it sit so I could finish the wiring of the glow-plug relay.

Last Few Wires

how it looks now

During the harness rewire work, I left the glow-plug relay and related heavy wiring in the bus. I had cut the trigger wires (label-label-cut), but the hotwire supply and to-the-glow-plug wires were left alone believing that splicing wires that thick should be minimized. So, I had to re-integrate that circuit. The wires were clearly labeled, and long enough so the splicing was easy, and the relay holder clicked right into it's designated slot. All that remained above deck was tying down the ground ring terminal from the larger ECU plug; I leveraged the fusebox mounting screw after confirming it was a solid ground. The final result is pictured on the right here. Considering what it used to look like (top picture), it is hard to imagine these are actual before-after pictures.

Next, I moved down into the engine compartment. It was an unruly mess (see bottom picture). I had shoved the harness through the hole, and left everything else as it was. My first steps were to plot out where the various wires would go, and that started with the always-hot lines for the 2 donor relays (109, 180). The 180 supply line was a hideous hack I did when I had no money, but it worked. I have more resources now, but more importantly, I have a long enough wire of the right size. Once I determined how long a run I needed so the wires could run along the top of the engine compartment straight back from the spare tire well, turn 90* over the top of the engine hatch to the battery with some flex in the wires, I spliced in wires with ring terminals for the battery-top fuse box. Next, I moved to the remaining little wires for things like the alternator "D" signal and the coolant level.

wiring T12 to cable

A few of these little wires needed to be extended. I re-routed the coolant level 2-wire cable. It had previously run along the front of the engine. Now, it runs along the top of the engine compartment hatch like the rest of the signal wires from the engine. I wrapped the little wires into another plastic wrap, and tucked the cable into the wire loom holder along the top of the engine compartment over the hatch. I followed that with the power supply wires. Finally, I plugged in all of the T10's, the T12 and the 2-wire glow-plug harness. Believing everything was set, I removed the float charger, and started testing amp draws from the battery post to the battery connector. The draw could be measured in milli-amps, so I figured it was safe to put the battery cable on the battery and see where smoke came out. I'm kidding; with the care I took for the wiring, and the fact that 95% of the changes I made were on that one harness, everything should be fine. The only changes I made that were not on that harness were the always-hot supply lines and tying signals from the rear to the front for things like a low coolant light.

Of Course It Didn't Work

below deck unruly mess

Feeling relatively confident, I put the battery cable on the post. No clicking, no other noise. So far so good. Interesting... the dash-pod was not showing the odometer like it used to. Slightly puzzled, I went to turn the key to run. The starter tried to spin, so I knew I had something wrong. I pulled the starter relay, and tried again. This time, I heard a slight pop noise, and the battery discharged. Clearly something, or many somethings, are wrong. Neat.

Well, that's it for today. I am sure I will figure out what I did wrong, and I hope it will be a minor, simple thing. The wiring was well labelled, and the other modifications I made were small. I can tell you that I pulled the diode between the start signal and the run signal. I've decided that if I need to keep that, I will move it to the ignition switch and out of the fuse box. I will keep posting on my progress until I figure out what's wrong. I don't think it will take many hours of labor, but finding the time for those hours is the challenge. Thanks, as always, for following along-

Chasing the Hapy Electrical Gremlins (part 5)

Continuing the saga of re-doing the TDI-related wiring in the bus. Recall, this all started because I was not getting consistent signals at the computer from the accelerator pedal, 20 feet (7m) away. I got carried away with some wire cutting and suddenly, rather than just replacing the front-to-back wiring, I was replacing the fuse box. Today's post is about the wiring surgery.

Expose the Harness

I started simply: set the main harness on the kitchen table and then spend hours trying to figure it out. Many of the wires were still hidden within stretches of cloth tape, so that was the first task: cut that tape off. This is simple, but messy because that tape remains tacky. This black tacky ick gets all over your fingers, and sticks to things, like your kitchen table. My wife loves me. I found that Goof Off was very helpful getting the sticky off of the wires (and the kitchen table). Once all of the wiring is separated from the wraps, and wiped down, we can start thinking through the various wires.

Wiring

My first order was to consider how much length I needed between the different pieces. For example, the distance from the bottom of the fuse box to the dashpod is less than a foot. In between them, I have the pass-thru hole below deck. I figured that the cleanest look from up-top would be for only the connectors to be above. So, that moved the T10 connections below, but I wanted them close. So, I shortened the wires from the main harness to the T10 connectors so they were all close together. Into this mix, I
added what I labeled a "T12". I purchased a 12-pin male and female connector to go between the front-to-back cable and the main harness. This is so that I can disconnect it like the T10's. Once the T10's were at length, I started integrating the T12. Not all of these connections go directly into the main harness though. Reference the post listing the T12 here. Circuits 1-6, 8, 9 and 11 tie into the main harness. That left 7 and 10 for the next step: the fuse box.

With the final extra wiring removed, the T10's arranged and most of the T12 integrated, it was time to consider the fuse box. I had already defined where in the bus it would be, but it also needed to be located in the right place within the harness, so the wires were not stressed, nor flopping all around. I used the dash pod plugs as a reference point, and considered the plan above as I decided. Since the middle of the harness will be below-deck, it was okay for the wires to be a little long. Once the location was determined, I started thinking about the relays. The relay box has 6 relay slots, but 5 are designed for standard Bosch relays (30-85-86-87 pins, with a middle pin for 87a). That's great for my start and run relays, but not so great for the glow plug (180) or main power (109) relays. Those have particular pin patterns. So, getting them to integrate with the pre-formed relay slots would take some customization.

 

Integrating the Donor Relays

I had designated on my wiring diagram that relay slots 1 and 2 would be the glow plug and power relays respectively. In the original relay plastic, they used to slot into #10 and #12 respectively. Each of these original plastic retainers have a little cut out to allow the fit of a specific relay holder. Fortunately, #11 is exactly like #10 (while #12 is different). I realized I could cut #11 and #12 out of the original retainer, clean them up and super-glue those retainer into slots 1 and 2. With some careful cutting with a hacksaw, I removed the 2 holders, and managed to fit them into the fuse / relay box. In order to interact with the wiring for the fuses, I needed to clearance the top, front edge. Also, because of the super-large size of the 180 and 109 relays, as well as the size of the relay retainers, they are super-glued in along the bottom edge, leaving about 1/4" of overlap for the super-glue to hold. Still, super-glue is amazing stuff, and with just that little edge, these original retainers are absolutely held fast, even when I put a little wiggle-pressure on the wires.

Fuse by Fuse

With the original relay retainers in place for the 2 big relays, I was ready to get after the fuses. Now, recall that I had this bus running with about 7 of the original fuses still plugged in. I discovered, however, that I really only need 4 of them: 29, 32, 34 and 43. I still had fuses 11, 12 and 15 plugged in and wired up, though. I have ported all of them over. Former fuses 11 and 15 share a fuse in the new box (fuse #1) because they appear to not really be necessary, but the wiring was there, so they are wired up now. Fuse 12 (now fuse 2) is to supply power to the OBD-II port in the wiring compartment. I expect this to be consumed almost never.

 

The other 4 had been clearly marked during my label-label-cut process. I had left myself plenty of wire so I did not have to extend any of them, which was very fortunate. For all of the fuses, the "consume" side is the front or furthest-from-the-relay side. As I wired in, I set the wires down so they would exit the fuse / relay box towards the front. Next, I did the supply side of the fuses, wiring fuses 1-3 together and then over towards the "RUN" relay and fuses 4-6 together and then towards relay 109. In the wiring diagram, fuse 29 gets it's switched power from the ignition, not through relay 109 so this is a correct reflection, though a little weird. I think it is through this circuit that the ECU is notified that the key is in "RUN" so it should trigger relay 109.

Relays

So, the fuses are done, the relay retainers for 109 and 180 are super-glued in. Next, we get the other relays wired in. I actually did 4, but I am only going to write about the "RUN" and the "START" relays. The other 2 I'll get to later. RUN and START are basic Bosch-style relays. A signal arrives from the ignition switch into pin 85 or 86, that signal difference is compared against a ground at the other 85 or 86 pin. Once triggered, pin 30 is connected to pin 87. So, for our purpose, the pin 30 for both of these is connected to always-hot, the 86 pin is grounded, the 85 pin wires into the T12 (7 for start, 10 for run). Pin 87 is where things get interesting. Pin 87 from the START relay connects to T6 to send a start signal to the starter. Pin 87 from the RUN relay connects to fuses 1-3.

 

Similar to the relay set up I had before, I wired in a one-way diode between the START trigger and the RUN trigger. Recall, this is because some ignition switches will not send a 12V signal down the RUN circuit while sending one down the START. When this happens without that diode, the second you try to start the engine, the computer thinks you turned the key to off, so it won't start. This diode allows 12V across from the START side to the RUN side, but not the other way. With a multi-meter, you can check this: negative on one and then the other, you can read connectivity, but only one way. Very cool. Last, the reverse light signal will be integrated into the switched circuit, but that is the only bus-related cross-wire (with an integrated fuse. of course). I did that because switched power was needed, and the consuming wire for it going to the switch on the transaxle was less than a meter away.

 

Last, I did the wiring related to relay 109, leaving the always hot circuit 30 to be determined once I got back out to the bus. Without that all the extra relay stuff, the hot wire had been cut out. I can now see that the actual demand on the 109 will be minimal (like 30A) in my implementation, so I will be replacing the old 2ga supply wire with a smaller one.

 

Once I was satisfied with the kitchen table wiring job, I took the whole contraption out to the bus for a test fit. Everything looked workable, so I brought it all back inside to wire-wrap. I used that plastic tube style available at Harbor Freight for all of the wiring clumps that run from a plug to the main harness, and from the fuse / relay box to the main. This left a few wires that still have label tags on them for things like the alternator signal and the coolant level. Both of those (alt and coolant level) are related to idiot lights I wired into the 6-wire cable when I did the oil pressure stuff (see Oil Pressure and Temperature - Part 4) so I will deal with those once I get out to the bus. All of these little wires have a partner in the engine compartment, so I will solve for them as part of the next phase: install.

That's all for today. This literally took me days. After many years of working at a place that shut down between Christmas and NewYears, I have grown very accustomed to having that week. In past years I have redone the seats in the MG or rebuilt a front end. This year, I spent most of that week doing the wiring, fuse / relay box stuff I just described. Yeah, this is a serious time killer. But, if Hapy starts on the first try, doesn't drop into that 1200RPM mode ever again and the wiring is no longer an eyesore, then it was all worth it. Thanks, as always, for following along. Please keep wearing your mask. These CoViD numbers are still very scary--

Chasing the Hapy Electrical Gremlins (part 4)

Before I begin, I hope we all have a 2021 that allows us to all forget just how bad 2020 was. That really capped off quite a decade. Anyway, with the new decade now in front of us, let's all work together on making our little worlds more friendly, livable and Hapy. On that, I spent way more hours than I could count over the last few weeks clowning on this wiring. I work slowly, so even when I have a huge block of time, meticulous work takes nearly forever. I got so carried away in fact, I missed my usual posting day this week, so this one is a little late. HNY!

 

Wiring Diagram

I have completed the wiring diagram. I mentioned in a comment on that last post that I had to start over because of differences between the Jetta and New Beetle of the same year. So goes. I now have a 12-page custom wiring diagram for this build. It includes things that I have not yet completed nor posted about (like a glow-plug light), but it does NOT include anything about the original bus. So, when working on something related to the TDI, we use this new one. When addressing something in the 50-year old transporter, we reference the Bentley. I expect that I will be making small modifications to the diagram based on what happens during the harness surgery. I figure that if the diagram isn't accurate, it really isn't very valuable.

 

Complete the Cut-Apart
When I last posted, I was in the process of cutting down the part of the wiring harness that ties into the fuse box and relays. I have worked on this area before. In retrospect, I maintain that leaving the engine harnesses that go to the ECU untouched is the right answer. I had looked at cutting them down too, and concluded that is playing with fire. Besides, just this one harness was quite a time consumer. This harness has the T10 plugs (white, black, orange, blue) and a T6 that in the NewBeetle's case is red, but on other cars it is brown. As I mentioned, this also has the fuse box, and relays. It also includes the dashpod, an OBD-II plug, an oval "T10" that is also black that lives in the engine compartment and there are a handful of little 2 or 3 pin plugs for the alternator, air conditioning and coolant level. It's really a random collection of things; making a decent custom harness from it is not all that easy. Anyway, my goal was to label-label-cut enough so I could remove the harness and thin it out. After the over-zealous cutting I mentioned in my last post, this was going to get much bigger. I got the last few of that "handful of little things" label-label-cut so I could bring the whole thing onto my kitchen table. I will get into the thinning in a future post (probably my next one).

Install Plan

Few things that go well happen purely accidentally. You have to make a plan. With the fuse box, relays and dashpod out of the way, I could re-assess the spare tire well which I'm now calling the "wiring compartment". I need to keep the dashpod wired-in for the engine to run correctly. Since it is rather small, I planned for it to go into the far end of the compartment, with the rounded top slightly pitched so I can see it when I'm tinkering with the compartment exposed. On the other end, nearest the rear hatch, I planned to put the ECU, with the new fuse/relay box in between. For this to work, I'll need to shorten many wires in the harness I just removed, but the result will be a wiring compartment with a few cables, but no spaghetti. The T10's will plug into the thicker ECU harness below deck, so there will be some cleaning, arranging or obfuscating I'll need to do there.

Dashpod Mount

The donor pieces I received included the plastic surround for the New Beetle dash. The front/top cover snaps in place, hiding the screws that hold the dashpod to the plastic mount. This cover, however, makes the dashpod too wide to fit in the spare tire well, so I tossed it. I also had to cut down the plastic mount so it would fit, leaving the front-most flat section and the lower plastic bits that support the screw-holes for the dashpod. The second picture from the top shows the dashpod in 2 pieces. The upper 2 pieces were cut apart. I set and reset, fiddled with and eventually arrived at a spot for the dashpod. I marked holes, drilled them out and sent long screws thru the dashpod mount into the front curved side of the tire well. The dash pod clicked into place, and was quickly screwed into place. I checked clearance for the 2 cables that click into the dash pod, and there were no issues.

ECU (computer) Mount

Mounting the computer was not as simple. I received what looked like the plastic ECU holder back when I first got the New Beetle TDI, but I could not figure out how to orient the ECU so it would fit between the base and the protective flap door thing. So, I tossed the base, and screwed the flap door into the spare tire well instead. The ECU sits quite nicely on there and the cables are unimpeded. I will need to either Velcro the ECU to the mount or use something else. I will use short hook-end straps (like these) for now, since I have a few of them, so they are free. I intend to treat myself (and Hapy) to a Malone tune, eventually. I'll go Velcro after that, since I don't know how the Malone tune thing works with sending a computer in or if you get a flash download or what. Something to learn, and post about later, I guess.

Fuse / Relay Box Mount

final-ish look

With the ECU and dashpod located, there was really only just enough room for that fuse/relay box to fit between them as you can see from the picture on the side here. I chose to locate it on the inside of the wheel well, but it could just as easily gone on the other side. This way, the fuses are furthest from the rear hatch, but the orientation is consistent with my drawings (where I have the fuses at the top). This was a relatively simple matter of aligning the top of the closed fuse box with the top of the rear deck, marking the spots and boring them out. A standard hand drill doesn't fit there, so I put the drill bit in my Dremel. That is probably not the best solution, so I don't recommend it, but without one of those fancy 90* air-powered drill things, we make do with what we have.

 

That's it for today. Next time, I intend to get into the harness surgery. Thanks for following along and Hapy New Year-

Chasing the Hapy Electrical Gremlins (part 3)

Continuing on our journey through the darkness of the wiring rat's nest.

 

Shouldn't Have Cut That

not quite "before",
dashpod already pulled

I'll just jump right into the interesting part. Well, mostly. I started in the engine compartment and removed the wiring related to the coolant heater first: the relay box, the wires down to the glow plugs, etc. That much was great. Then, I moved on to looking at some of the wiring above, and as the bold-faced line implies, I cut something I would best not have.

 

Reflect back to the last time I clowned around on this wiring, I dug deep into the fuse-box. I started by pulling the fuses for circuits Hap doesn't need. Circuit by circuit, I cut that unnecessary wiring by referencing fuse sockets where the fuses had been pulled. That plan worked great. Lots of extra wiring got removed, and the engine still ran. I still had the sporadic not-limp-mode, and the occasional Hapy-don't-wanna-start issues, but they both seemed improved. Well, this time around, I got into the fusebox and saw a few wires that did not appear to have a partner on the other side of the fuse. So, I figured I just missed them the first time, and cut them. Well, that was wrong. Their "missing partner" was actually a common-line always-hot (circuit 30 in VW-speak) that was kind of hidden from view. Well, I didn't see them anyway. The wires I cut are for powering "engine control" circuits, of course. So, kinda important. Ugh.

Fuse Box Smaller

don't actually need
any of these relays

Once I realized that the wires I cut were critical, I needed a new plan. A while back, I bought a small relay box thing off eBay that has 6 relay slots and 6 fuse sockets. Once it arrived, I looked at how many fuses were in the donor fuse box and how many sockets were in that smaller box and the math did not add up. That was all before I did the clear out I mentioned above. After that, I was down to 7 fuses, and one of them was for the OBDII plug that I don't actually use. So, I think the fuse socket numbers may work. As for the relays, I only need 2 of the donor relays: the infamous 109 (main power) and old 180 (glow plugs). All the other ones can go, which leaves me 4 slots for other things, like the "RUN" and "START" trigger relays I have connecting the ignition from the front to the electrical from the donor. Neat. I didn't mean to change the fuse box and the relay plastic holder thing, but when I cut those two engine control wires the die was cast.

Label, Label, Cut

smarter way to remove
extra wiring

So, into the darkness we go. I started with the more obvious wires, like the thin little wires on the 180 (glow plug) relay. Then, I moved on to the T10 plugs. There are 5 (Blue, White, Black, Orange and Brown) 10-pin plugs in the mix of all that rat-nest. I unplugged them, and started dissecting by labeling either side of the cut, describing what is on the other side, and cutting. This picture on the right here explains the wire coming from the ignition switch position 86s as an example of how I dealt wit the wire-snarl.

While that sounds like quick work, I have moved slowly, researching each wire first, to make sure I don't have another "engine control" mishap. And, I want to do more than just label where it went; I want to know what it does first. This is a lot like a jigsaw puzzle where the more you do, the faster it goes until you eventually have all of the wires you intend to cut labelled and cut apart. I am almost done, which means the next post on wiring should include some building back up.

Diagramming

One last thing I have been doing, is crafting my own wiring diagram. I started by scanned the wiring diagram for the early ALH engine (80-pin ECU) from the Bentley. There are 13 pages. I am examining each circuit across the diagram and editing the image of the page to reflect what my circuitry will look like. I am retaining the original circuit numbering, etc. but adding the number of the fuse that I am using in the new fuse box to the documentation. Perhaps more importantly, I am erasing the wire references to things that I no longer have, like the coolant warming glow-plug stuff. My thinking is that this way someone who knows the original wiring (looking at you, Justin) can understand the diagram just as well as I do. This diagram will replace the diagrams in the 3-ring binder, since the 2 sets in there are both for later ALH models, so they are informative, but not exactly 100% representative. Between the cold and the dark, the diagramming effort helps me feel like I am moving forward while also creating clarity around the work.

My CoViD-19 Plea

I take a 2 mile walk pretty much every day to shake off the cabin fever and to get some exercise. Every day, I see 20-30 people also out taking walks, riding bikes or taking a run as well. That's great except I can count on one hand the number of people I encounter with a mask on at all (even worn wrong). The other day, I counted 3 people out of 28. Seriously. Our tiny state is consistently seeing over 1200 new cases a day, which is alarming when you consider our "summer peak" was 430 cases a day. Please keep your masks on, its not a political statement, it's not a chin-strap and it doesn't work unless it covers your nose and mouth. It's to protect others from you, not the other way around. We don't know if you have the virus or not, and quite frankly, if you're wandering around without a mask, and hanging around with others who don't have masks, then even if you had a test today... you don't know either. Just because you're outside doesn't mean you can run/walk/bike right past other people a-huffin and a-puffin (and sometimes a-coffin) without a mask. We are all tired of this, but that doesn't change anything about the importance of respecting it, and each other --