Weird Brake Light Issues

[Monty4248]

Bought a 2000 2.8 z3 roadster, came across an issue that has puzzled my friend and I as we progress with repairs. All three brake lights fail to turn on. All bulbs and sockets are tested to work, the brake sensor is fine, the fuse wasn't blown, we replaced some weird LED rear running lights, and grounds seem fine.

When you disconnect the passenger side rear cluster, the 3rd brake light starts working. And when you disconnect the driver's side rear cluster, the 3rd brake light works. the brake lights in both the rear clusters don't seem to work no matter what we do.

We've been having trouble figuring out what on earth is causing the issue. Any insight would be very much appreciated!

 

[NZ00Z3]

Hi

Here is your wiring diagram. Disconnect the rear right light assembly and test pin 2 of connector X318 for a stop light signal. If it there, start tracing the signal through the light assemblies.

 

[t-tony]

I would be looking at the so called "Loom of Doom" where the wiring exits the body at the left hand boot lid hinge area. Pull back the wrapping etc. and look for damaged cables.

Tony.

ps. If you don't get to the bottom of this before I come over to our home in Kissimmee again, maybe I'll be able to help.Damn this Covid 19.

 

[Monty4248]

I would be looking at the so called "Loom of Doom" where the wiring exits the body at the left hand boot lid hinge area. Pull back the wrapping etc. and look for damaged cables.

Tony.

ps. If you don't get to the bottom of this before I come over to our home in Kissimmee again, maybe I'll be able to help.Damn this Covid 19.

Hey, thanks for the advice. Wound up being the brake sensor.

 

[t-tony]

Hey, thanks for the advice. Wound up being the brake sensor.

Which brake sensor? Always useful.to give full info to help other users. Thank you.

Tony.