For background see this thread:

https://www.audiworld.com/forums/sho....php?t=2813948

Well, lo and behold, the cause of all these shennanigans was in fact a "slip joint" i.e. a yellow plastic connector between the "hot" (blue/red) wire to the driver power window switch, and a wire in the harness to the power mirror switch combo.

I am not kidding.

It would appear that the squirrels who wired the car wanted retained accessory power to the mirrors and simply jumped off the power window switch to the driver door. Or vice versa.

Seeing the ignition wired properly, and noting removal of the window relay (with Key out) enabled power still going to all windows minus the driver door, for ****es and giggles I thought perhaps the driver window switch was bad. Taking it apart (with key out) I noted some sparking noises from the aforementioned "slip joint"
I also noticed the Heater fan going on and off when I manually manipulated said joint. I removed the joint and whola--no more power going to 2/3 of the car's electrical system, and the wipers even return to "rest" position when they are switched off instead of stopping where they were. What I did notice, is that now the windows work as they should. When the key is off they work until the driver door is opened. Although the red light in the switch stays on but ever so dim. There are still millivolts going to it.
Removing this joint will probably cause other problems. I fully expect the starter to engage when the trunk lid is opened. Because the squirrels put that slip joint in for a reason, and expect something else is the power mirror circuit is bad.

I strongly advise B4 owners to check out this connection, because I personally observed a B4 in the junkyard with a driver door fire. At the time I thought it odd, how could a fire start in the door. Now we know. That slip joint was hot as it was sparking.

 

Thanks for the warning, I'm going to have to check this out.

 

Knock on wood but I have not had any electrical problems.

Are you saying this fitting was not crimped very good and thus it moved allowing the short?

 

Yes, correct. Apparently after a period of taking the door panel off/on, replacing switches, etc., it became loose. I've had several of these cars, and my '93 doesn't have it. My first 95 did have it, but it gave me no problems. I'm not exactly certain what the purpose of this thing is. If it is to connect the two sides together, i.e. the power window/power mirror wiring, why would a loose connection matter? The covering on the wire was through, and i am seeing copper on both sides when I remove this connector. If the purpose is to join these two circuits, that shouldn't have mattered or caused shorting. Perhaps someone can check their Bentlys wiring diagrams to see if it shows up there. After thinking on this, it just doesn't add up. All I know is, I had constant power going to most of the car with this connected, and removed I don't. no more power drain. No dead battery.

 

Is it possible somebody molested this connection by removing the door panel not in the proper way?
It's always hard to tell what a PO might do, someone who was clueless and just starting yanking stuff might have disturbed the otherwise solid fitting.

Some shops who just do not know Audi's well can do more harm then good.

I had this myself once before, the place actually replaced my fuel pump [which was new] with a used one because....hell I have no idea why.

Apparently they thought the Piersburg was the problem and installed a used Bosch, of course without even contacting me/asking me.

I never went there again.

 

Ok, i am having this EXACT same problem. I have been having to DC the battery constantly to keep it from dying. I am some what ignorant when it come to electrical stuff. (prolly something i should remedy since im an audi owner and lover) So what/where is this connection? (pic would be awesome if possible) i was having some difficulty following the other thread. You said your drivers side window doesnt work? My drivers rear is currently non-working, is this more than likely where my issue is going to be? Or is this specifically the front doors? (i do recall some mention of the power mirrors). Also on a possibly related note, my car has decided to not start. I checked the battery and it has good charge. I also only hear the fuel pump prime every couple of key turns. All of the lights dim when i try to crank as if the battery is dead. My first thought was the starter. But im wondering if i dont have a complete wiring cluster f*ck somewhere. I pulled the stereo and the under dash pad out and there is wire spliced EVERYWHERE. Connectors just hanging loose and all kinds of a mess. I should mention that this is a 1990 90 quattro 20v, With a 10v motor swap. (I didnt do it and i dont know the person who did, i would b*tch slap them if i could) Any and all help is deeply appreciated.

 

Dude you are screwed. These cars are a big enough electrical nightmare with untouched factory wiring. From your description someone already made sweet passionate love to the wiring harness before you got to it.
I would suggest getting one of those battery cables where you can cut power to the car. When you drive it, the battery cable is "on" and When you park it, turn the battery connection "off." No more battery drain then.
Trying figure out what someone else did, and being 'somewhat ignorant' with electrical stuff, I wouldn't even try to figure out what someone else did.

 

where could i find a wiring diagram for this thing? I am somewhat ignorant, but im a fast learner and am confident in tackling this. Upon further inspection, it would seem that most of the splicing was from whatever jack wad installed the stereo. Instead of just buying the proper wiring harness to hook the aftermarket stereo into the stock amp system. They decided it was more appropriate to run what i believe to be the remote wire down under the dash and splice it in, and hack into the rear speaker wire, and run X amount of extra wire all the way back to the rear speakers. There does seem to be a few wires with electrical tape in a few spots, but best i can tell, they aren't spliced. I still have some connections under dash that are open, not ssure what they are for and if i should be reconnecting them. But anyway, back to the issue at hand, I did smell what seemed to be burning plastic a few times. Almost like that heater smell that you get when it hasnt been used in awhile. I think i will pull the door panel off and see what i find. But i still need help figuring out the no start issue. O, just remembered that when i turn the key, the rpm gauge goes up sometimes... wtf? Any thoughts?

 

Full Bentley Manual has wiring diagram.

Depending on where the harness is, you might be able to snag a good harness from a pick n pull - but only for some sections. Certain harness are long and routed thru firewall, etc., and would not be worth effort to replace.