Do the red door warning lights operate independently? My 91 740 works like this ...The front left or right door has to be open for any of the rear lights to come on. The drivers door light does not come on when open which leads me to think that something is screwy..I tested the bulb and it is good. I will test for a good ground tomorrow..How does yours work????

There is one phillips screw holding the switch in place at the front of the door. Since the driver's door get used the most this is the switch is is most likely to go bad. Take out the switch, undo the electrical connections and pry apart the switch. I would not be suprised to find it full of gunk. The small metal contacts that operate the switch may have disintegrated as well. I cleaned 3 of mine but the driver's door switch I had to replace.

Jes

Just like uberbox said. Until a month ago I had no lights when I opened any door, and I took out all the switches and totally disassembled them, sanded the contacts down, and even bent a few to contact better. Now the red lights and my interior lights work great! You may not, however, be able to fix these switches, because it is delicate work to disassemble them and sand the contacts, so if you don't want to do that, get some new ones.

Good luck!
Dan

I removed the drivers side door switch and found that someone had previously disconnected what I suspect was the ground wire and connected another to the switch and secured to the cars frame with the securing screw. Perhaps the original "ground" wire lost its ground. I will investigate further and post
findings..cheers