Reply to SERIOUS ELECTRICAL PROBLEM
You certainly have my sympathy with all of the little gremlins that appear to be plaguing your car. I've been there with a different car and drove me crazy.
Try something simple first. Replace EVERY fuse in the fuse block with a new one. Don't even think about keeping any of them, just throw them away. While they may look good, sometimes theres a problem that is not readily apparent. It's a cheap way to be certain.
Clean both sides of where the fuse is inserted with a plastic wool pad (3M 'scuff pad' or equivalent) and then place the new fuses where they belong. REMEMBER, make a chart of where the 8 amp ones go, the 16 amp ones go and the 25 amp ones go.
I've done this on a couple of our cars now when something 'funny' begins to happen and it has eliminated a lot of potential headaches.
Scotts Valley, CA.
1993 300 CE Cabriolet (A124) 131K miles
1997 C-280 133K miles
2000 BMW R1100RT 69K miles
1989 300 E 216K miles (sold)