Hey,

My 1997 GMC Jimmy's brake lights won't work. The top LED brake light works fine though. When I turn on the headlights, the running brake lights turn on as they should. The hazards and signal dont work in the rear either. Everything in the front works perfect.

I've checked all fuses and bulbs.
I just changed the the multifunction switch.

Still having the same problem.

Could the brake light switch cause the the LED brake light to work properly and cause the two lowers ones to malfunction??

Thanks.

 

Hmm.. if the brake lights and hazards dont work that should be a fuse because they are both on the same fuse. that has happened to me 3 times (i got a short somewhere) and a blown fuse has always been the problem. but are you sure you checked every fuse on the side of the dash? it should be a 20 amp fuse.

 

Yea they all are intact. The contacts look a little bit worn but the fuse is good.

 

Check the white wire at pin A1 of the multifunction switch for +12V when the brake pedal is pressed. With the connectors to the multifunction switch disconnected, check for continuity between pin A1 & pins E6 & E7.

THIS THREAD has the wiring schematic for the exterior lights on your truck and may also provide some insight into your problem.