I have a 95 525i (E34). On my OBC in the dash the Brake LT Curcuit is on. I have checked the manual and it says that a bulb is defective, or take it to the dealer. Does anyone know what this is? Is it very costly? Please let me know, I want to know what it is before I take it to the dealer.

Just replace the bulb.

What bulb?

The brake light bulb. Check to see which one is out.

All of them are working, I looked up this and found that the stop light switch causes the brake lt circuit to go off. Is this the problem?

Stop light switch? You mean the hazard lights? I'm not sure what exactly is happening here. If you're getting a message from the OBC when you turn on your hazards, that's wierd... maybe you should take it in to the dealer.

check to see you are using the correct bulbs. (more than one type of bulb may fit the socket, but it may not be the correct one)

check to see contacts are clean.

are you using aftermarket tail lights by any chance?

i don't think the brake light switch is bad. if the brake light switch was bad, i don't think your brake lights would be working at all.

Just thought of something else. Try replacing the fuse. You can find the number for the brake light under your fuse box (LKM) cover.

I saw alot of info when I did a search for brake circuit, the E36's are famous for this problem, it is a switch located under the brake pedal.($16 switch) I will try ckecking the bulb, since I just replaced a brake light and have been geting this error. All the brake lights are in working order. Just don't know

I get this every now and then when it rains. Never in the dry. Brakes and Brake lights all work fine. I have correct bulbs, etc.