Having a very similar problem to sp0rky's (I think)
Is it just really waaay too cold out?
My dash used to come up with "Brake Light Circuit" every couple of days. Only my left brake light will go out. Soon this became a constant problem and my left brake/tail light will go out. My turn signals operate perfectly.
I assumed this was the cheap bulbs that came with my after market tail lights.
Replaced all the bulbs today. It's 18*F outside. took taillight out and replaced all bulbs. Right side brake light no longer functions. Left side is completely out except for turn signals.
More disturbing. As I was driving my car out of the parking lot my gauge cluster worked for a few seconds, then died. No gauges function. I can get my spedometer and tachometer working by pressing the reset button for the trip odometer. This causes the odometer readings to light up for a few minutes before they die again. Temperature guage, Fuel Guage, Mileage, spedometer and tachometer fail to work. Turn signals and ASC display properly when I press buttons.
Notice #1 Fuse was blown. Cruise control, taillights... etc. Replaced fuse. Guage cluster worked for 30 seconds before fuse blew again.
Got home. Started googling. Replaced LKM with another one I had lying around. Replaced #1 fuse again.
Fuse did not blow, but guage cluster still doesn't work. Taillights still running into trouble.
I thought about doing this: BMW E34 Website
in order to fix the problem... I'd like to avoid it though. Does anyone have any idea what could be causing this? It seems like so many of the car's systems are tied to that fuse, what should I check first?