ok, I have been looking for some time now on line and cant figure out what to do next. I had a bad CTM, changed that but before that i lost rear brakes lights except for the 3rd one. Then in the mddle of the night the 3rd would turn on and stay on. I checked my rear bulbs and sockets, no power to the brake light part. I have tail lights but still no brake lights. changed the brake switch by brake pedal now nothing. no back 2 or 3rd now. What next?

 

Check fuse 5 in the PDC under the hood. It feeds the brake lights.

Do the turn signals work?

 

Fuse good under hood and checked all by drivers door. turn signals good haz good

 

Time to grab the factory service manual and see where the voltage goes to the brake light switch, from the brake light switch to the multi function switch, etc.

Also, make sure the new switch isn't defective. If you unplug it and jump the terminals, the 3rd brake light should light up if the power to the switch is good.

RwP

 

The output from the brake light switch feeds the 3rd brake light and the combination flasher.

Did you properly adjust the brake light switch when you installed it? It's a one time deal.