Dashboard and taillight problems

[jacksonpat1008]

PLEASE HELP, i was at tail of the dragon when the backlight to my dashboard went out as well as all the interior back lights, the tacometer/speedometer still works and i still see my parking brake light, dsc, etc... i have already replaced the rheostat with a used one i bought off of ebay that appeared in 100% working condition. Still no fix to the issue. I have checked all of the lighting fuses... not a single one has blown or gone bad, on top of that my right parking light doesnt cut on (the blinker still works) and worst of all my taillight doesnt work (brake light bulb works though) and i have checked all of the taillight bulbs to find that they are all 100% okay. I havent begun digging around the wiring harness looking for a bad wire but i have a 70k mile z3 in very very good condition that has given me no problems so i couldnt see that being an issue

[LaRy]

I've been digging into the electrical drawings in your case. Seems like fuse F33 and F37 are involved, but those are ok, I assume.
The only thing in common, and physical also close together, is the the light switch.
For Z3, 1997- 1998 the following information i valid.
All measurements on the light switch terminals:
Power all time on 5 and 7, straight from fuses.
When switch is in on position: 1, tail lights left, grey/violet
12, tail light right side, grey/yellow
6, instrument cluster with reostat, grey/red
8, license plate light, /black

I guess the light switch has collapse inside. Short circuit or equal.

[Robert T]

I've also been looking at the ETM and it looks like fuse F33 is common to all those. How did you test the fuse? A visual inspection is not enough. I've seen fuses that look good, but are in fact blown. You need to check it with a multimeter. You can also try replacing the fuse, but this may burn out immediately if you still have a short circuit somewhere. Common places for shorts are the backlit gear knob and the boot/turn light.

Also, a few other things to check - does the licence plate light work? Do the windscreen wipers/washers still work?

Cheers R.