AnotherS197GT
Serial Valve Dropper
On Sunday I was informed that my brake lights weren't working by another driver on the road. I checked the fuse in the SJB and it had popped. I replaced it with another 10A fuse and it popped as soon as I hit the pedal. I tried unplugging the brake lights and tested again to see if there was a problem with the tail light harnesses. The fuse still popped.
Yesterday I spent some time trying to diag the problem and this is what I came up with:
I have power in the BEC, power at the SJB, but no power at the brake switch.
I tested continuity on the wire that feeds the brake switch and it's good. Jumped voltage to it and got a full 12V+ on the other end.
Tested continuity on the fuse for the brake switch, it's good.
Pulled the SJB apart and tested continuity on the brake light circuits. All good. (pins 10, 11, 16)
I reassembled everything and the lights were working fine last night. This morning, they're not working anymore. The last time I tested the brake switch with the SJB plugged in, there was no voltage at the brake switch. I'm going to test again tonight, but I doubt anything has changed. At this point, I'm leaning towards a dead or dying SJB, but it seems like it should work or at least send 12V to the brake light switch.
Turn signals, hazards, parking lights all work just fine. Only the brake circuit is not working.
Yesterday I spent some time trying to diag the problem and this is what I came up with:
I have power in the BEC, power at the SJB, but no power at the brake switch.
I tested continuity on the wire that feeds the brake switch and it's good. Jumped voltage to it and got a full 12V+ on the other end.
Tested continuity on the fuse for the brake switch, it's good.
Pulled the SJB apart and tested continuity on the brake light circuits. All good. (pins 10, 11, 16)
I reassembled everything and the lights were working fine last night. This morning, they're not working anymore. The last time I tested the brake switch with the SJB plugged in, there was no voltage at the brake switch. I'm going to test again tonight, but I doubt anything has changed. At this point, I'm leaning towards a dead or dying SJB, but it seems like it should work or at least send 12V to the brake light switch.
Turn signals, hazards, parking lights all work just fine. Only the brake circuit is not working.
Last edited: