Hello, I am new to the forum, since I just bought a 1998 ti with the sports "M" package.
The rear brake lights are not working (the tail lights and the third center one)... I checked the fuse #46 under the hood and ok, the 15 amp fuse in the rear tail light is ok and the bulbs are brand new.
Any thoughts on how to fix this problem. Any help would be great...
How are ytour instrument clustr gauges? Your gas and Temp. I had a problem similar to this. Where there wasa short because someone had replaced a light with the wrong bulb... Save yours self some moeny ... open the light thing check all the bulbs make sure there are no copper unded bulbs they shoudl all be silver. Cant remember right now what kind of metall they should be but check them before you take it anywhere. Look again on your fuses i think their might be a couple fuses that link to the brake lights.
This is a silly question but it had me chasing my tail for a little while. Is your car on or the key turned to the ACC position? BMW brake lights dont come on unless the car is on or at least the key in the ACC position. I have never had another car that acted this way until we got my wife her 330i and it is the same way. All my other cars the brake lights worked all the time. Also if that is not the case you might want to search on brake light switch on bimmerforums.com for a DIY to replace the $20 brake light switch that is attached to the brake pedal under the dash.
I checked all the bulbs and they are the correct type and working also fuse #46 is ok under the hood.
I checked the switch under the dash and it is woking fine (I tested it with my volt meter) I also bypassed the swith. The problem is now from under the dash to the rear lights.
The Question Becomes: what happends between the switch under the dash to the rear lights.
Does anyone have any wiring diagrams for the brake lights????
I believe that all the wiring for the car goes through the driver's side sandwiched between the door panels. I'll see if I can get a wire color for you.
__________________ I scream, you scream, we all scream for ZOMBIES.
Blue / Gray hash-stripe from switch Blue / Red from check-control to Right Blue / Brown from check-control to Left
There is also a Blue / Yellow hash-stripe going between the lights.
I'm thinking I'm probably wrong about the wiring going through the driver's side, since I forgot about the gas flap lock. However, there's a large snake of wires on the driver's side, and I would start there.
__________________ I scream, you scream, we all scream for ZOMBIES.
I took out the back side panel and played with my volt meter and the massive bowl of Spaghetti of wires until I found the one that was cut and shortening out... Wire replaced and problem fixed
Brake light Problem 
(the tail lights and the third center one)... I checked the fuse #46 under the hood and ok, the 15 amp fuse in the rear tail light is ok and the bulbs are brand new. 
Linear Mode
