1986 745T
I'm still struggling with this electrical problem.

I've disconnected the interior lights, pulled the bulbs from the door lights, removed the engine-hood light, removed the radio and isolated the wire going to the clock/glove box/ vanity mirror.

I removed the offending wires (double wire to the doors/dome and the double wire to the engine/cargo areas) at the fusebox and connected an ohm meter between them and a chassis ground.

Both read "0" - no resistance.
I open the driver's door and there is no change to the doors/dome wire.
I then just touch the door light bulb to it's contacts and remove it and the resistance indicated on the meter starts going up slowly. I guess it ultimately reaches infinity given a few minutes (the meter only goes up to 200 ohms).

The wire for the engine / cargo area light shows "0" resistance from wire to chassis at all times.

In desperation, I removed the wires from the alternator and the symptoms remain.
Battery connected or disconnected and the symptoms remain.

I've checked the wires above the headliner and do not have any shorts there.
The car has never been in an accident and the ground connections that I can see appear to be clean and not corroded. However, I'm beginning to suspect the grounding of the door switches. I checked the switches themselves and all seem ok. Is there a main connection for the grounding of the switches?

Thanks for listening. So far I've been running in circles for about 20 - 25 hours on this stinking problem and need to vent!