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Sam, BMW Master technician
Category: BMW
Satisfied Customers: 1043
Experience:  BMW S.T.E.P. graduate, 10 years BMW dealership experience
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BMW Z3 brakes lights not working

Customer Question

Power top and cruise control started to work intermitently and then not at all...the brake lights also stopped working...I have been told that installing a different brake light bulb may have affected the wiring...I did notice discoloration and what appeared to be rust on one of the brake light sockets...I replaced the sockets and bulbs from the dealer parts...I am at a loss as to what to do next...any suggestions?
Submitted: 8 years ago.
Category: BMW
Expert:  Sam replied 8 years ago.
Did all of the brake lights stop working at the same time?
Customer: replied 8 years ago.
No, I believe I replaced just a single bulb and that could have been when the problems started...I'm just not 100% positive
Expert:  Sam replied 8 years ago.
Have you checked the fuse for the brake lights?
Customer: replied 8 years ago.
Yes, it keeps blowing the fuse...15 amp
Expert:  Sam replied 8 years ago.
Which number fuse is blowing?
Customer: replied 8 years ago.
I believe it's position 46 on the fuse panel
Expert:  Sam replied 8 years ago.

That is the main fuese for the brake light circuit.


Does the fuse blow right when you plug the new one in?


Will the fuse blow if the switch is operated with no bulbs/sockets installed?

Customer: replied 8 years ago.
The fuse blows when I use the brake pedal not when I plug a new fuse in...The fuse still blows if the brake light bulbs and sockets are removed
Expert:  Sam replied 8 years ago.

Was there anything that triggered this to happen?


You mentioned something about "different" brake light bulbs. What made them different?


Has the car been in an accident?


Why was the convertible top switch replaced?

Customer: replied 8 years ago.
No...I was told by the bmw dealership that an over the counter bulb was different than theirs...the car has not been in an accident...I replaced the top swithches early on when the top stopped working and then the interior switch for the top control not knowing I had no brake lights at all
Expert:  Sam replied 8 years ago.

Sorry about the wait, I had to step out for a minute.


There is a short in the system. Do you have a volt/ohm meter and the ability to do some electrical diagnosis?

Customer: replied 8 years ago.
no I dont have a volt meter but could probably handle diagnosis with some guidance. I could get a volt meter this you recommend any in particular?
Expert:  Sam replied 8 years ago.

No particular brand is nessecary, just one that can measure voltage and resistance.


How did this issue present itself? Did the lights just stop working one day?

Customer: replied 8 years ago.

I didn't realize I had an issue with the brakes until a friend following me told me. I don't feel safe driving at this time and would not want to be the cause of an accident. I have another vehicle but would like to fix all of the related issues with the Z.

I will get a volt meter today before work and try to contact you.I work on Sunday and Monday but can test related items on Tuesday. It would be great if you could give me a little advice before Tuesday. Thank you very much!

Expert:  Sam replied 8 years ago.

I can give you advise on whatever you need. Let me know what you need advise on.


We can do it when you get time, I'll be here.