Power windows and dash lighting out - wiring diagrams?

[Theotherotter]

I recently got my E12 going again after the cooling fan yeeted itself in October in South Bend, IN. I can’t wrench in the winter, so I had to wait a while. Surprisingly, the radiator was still repairable! Anyway, I noticed that my power windows were inop. I assumed that I had reconnected the wiring to the fuses on the kick panel wrong - I checked, and it was correct. Hmm. But when I took the car for a checkout drive, I noticed that my dash lighting was also out - cluster and HVAC control lighting. Looking at the labeling on the fuse panel in the engine compartment, it’s not obvious to me how this could be accounted for in a single circuit. The gauges still work. I have an E28 manual, but I don’t have any E12 manuals that I can refer to for wiring diagrams. Do these exist online somewhere? I haven’t found them here.

[Mike W.]

They are in the Haynes manual, which unlike later ones is really an excellent resource. While I think it's out of print I strongly suggest you pick up a copy off ebay, there's several out there now. https://www.ebay.com/sch/i.html?_nkw=ha ... at=0Seeing as its in a bound book, it's really hard to scan or photo well, and the index is on a still different page.

Looks like the windows are fed off a relay, probably the relief relay, which is fed directly off the battery, no fuses anywhere, just the window breakers. The dash lighting not working either is odd since they're fed completely differently.

[Theotherotter]

Thanks, Mike. I went ahead and ordered a Haynes manual. I have a Chilton for an E28 that a friend gave me, but that only covers a limited amount of things for my E12. I'll have to see where that relay is, though given that it gets power directly from the battery, it can't be hard to find if it's not one of the relays in the fuse panel.

I think the dash lighting issue has to be independent of the window issue. My first thought was that they were related only because I last drove the car in October, when the windows worked and the dash lighting worked, and I noticed both things at the same time. But I did also see a rat dropping on the thermostat housing so I can't exclude a rodent-caused issue. Chicago is filled with rats and there is no way to avoid them in detached garages. I've been lucky never to have had issues with them yet.

[Mike W.]

IMO the E12 was about the last of the good Haynes manuals. Bavaria was good, E21 was good, E12 was good, E28 was lousy.

If it's fed from the relief relay, that one is in the fusebox.

[Theotherotter]

My Haynes manual arrived yesterday, and it will be a big help.

I am pretty certain that my problems were caused by rodents over the winter. I’ve been fortunate in that Iv’e never really had rodent issues over the years. Now was my time, I guess! Tree stayed away from the 911, though.

Inop functions are:
-right rear turn signal (brake light and reverse light work)
-right front marker lamp (turn signal works)
-right rear tail lamp
-dash lighting, center stack and clluster (gauges work)
-power windows

There are rodent droppings in various places in the engine compartment

I’ve looked at the wiring diagram in the Haynes manual and I’m a little confused about a few things - e.g. there is an object labeled “plug 1” - but where is this? For example.

Got some work ahead of me! Sigh.

[Theotherotter]

I've been able to eliminate rodents as a cause. Started with the obvious and easy step of cleaning the ends of all the fuses. A couple of them were good, but so fragile that they disintegrated when I hit them with the wire brush. Inop right-side marker light and dash lighting was caused by the contacts on the #9 fuse.

When I tried to remove the connector plug from the bus bar on the right taillight, the taillight went back on. So that one's due to an iffy wire connection on one side of the connector.

Right side rear marker is just a bad bulb. Left side is TBD. I did hit both connectors with DeOxit.

This mostly just leaves the power windows.

I fortunately I didn't have to go far beyond the easy first steps for most of this, but I had a conversation with Google Gemini to have it come up with a diagnostic plan for me and it was shockingly good.

[dsw99a]

OMG AI IS#1?

[Theotherotter]

So most of the success was me. But I can say that AI helped provide structure that gave me confidence in what I was doing. It helped me solve the problems more quickly than I would have otherwise, and the structure helped with my learning. It's kind of like having a teacher next to you walking you through new things. I'm an engineer by education and (sort of) by profession, but I'm a mechanical guy - I am a lot more at ease with, and have a better intuitive understanding of, mechanical (and hydraulic, etc) systems than of electronic ones. I recognize that my block was really mostly one of feeling intimidated and needing to get over or around that.

The key thing when you are asking AI to help you with many things, whether it's diagnostic procedure or writing a program to perform some operation for you or help you solve a problem, etc is the quality and nature of the conversation that you have with it in setting up and identifying the problem. In addition to giving it needed information (for example, in this case I didn't know where plug #1 (object #89) was located, but after giving it the wiring diagram and key, it told me exactly where to look), you need to keep asking it if it has any questions for you, until it has all its questions answered or says it has enough information to do what you're asking. After you've asked it to do whatever it is you're asking, you can then ask it to, say, compile everything in a Word document or a PDF, and you can ask it to then write an AI-to-AI prompt to automate the process for the next instance, so that the next time you have a similar ask of it you just feed it the prompt that it created. When you do this with the prompt, you can iterate it by running the new prompt on your newly solved problem (or something known) and refining it repeatedly until it stops changing. I've learned a lot about it from a friend who's work and capabilities have been radically changed by his use of it in less than a year.

it's also important to note that you have to check its work. For example, it told me that a given circuit was on fuse 8 when it was actually on fuse 9. It made other small mistakes that you have to be able to recognize (eg thinking the PW switches were located on the console, where they are on an E28, rather than on the driver's door.) and correct it on.

Only thing left to address is the rear side marker lights. One appears to have a bad bulb (it was hard to tell with my headlamp shining on it in the dark) - I'll probably remove both bulbs and test with my DMM.

Oh, and having a power probe is really handy.

The power windows are pretty slow, so I'm going to look at all the contacts in the circuit to see if there's anything that obviously needs cleaning, and remove the door trim panels to see if the motors and tracks would benefit from a cleaning and regreasing.

[Mike W.]

The power windows are pretty slow

IIRC 79's got upgraded motors in front which were faster, but expect 530s and rears to be slow. My guess would be the tracks need cleaning and regreasing.

[Theotherotter]

That's my guess, too. I'm going to remove the front door trim panels and do various things:

-inspect window tracks, clean and regrease as/if needed
-clean electrical contacts for window, mirror and lock controls
-front passenger window rattles a bit, identify and correct
-replace wood trim strip on passenger door
-replace window seals

Re: the last one, I mean the felt-like piece that goes around the perimeter of the window opening (not the wiper gasket at the base of the window) What's the best option for a replacement for this? The front right window has a piece that is loose and flaps in the wind.

[Mike W.]

Re: the last one, I mean the felt-like piece that goes around the perimeter of the window opening (not the wiper gasket at the base of the window) What's the best option for a replacement for this? The front right window has a piece that is loose and flaps in the wind.

https://www.firstfives.org/winchan.html

Is what I'd try.

[Theotherotter]

Thanks! I had checked the FAQ and missed that. I had a memory that I’d found it a good while ago and I thought I’d saved the information, but once I remembered the name of Restoration Specialties I couldn’t find it.