2002 GMC sierra brake lights not working. Reverse and blinkers ARE working!

First, verify that the brake lights work correctly with the old lights. If your blinkers work, the brake lights should work as well.
It is possible that your brake lights were not working previously. If they do not work, suspect a blown fuse or a defective brake light switch.

sounds like your switch on the brake pedal is bad or the wire between the pedal and the lights

Good Evening, there are a few simple things to check first off. The brake switch follow your brake pedal up and there is a rectangular box up there that could be at fault, or if you take one of your tail lights out and have someone step on the brakes you could take a test light to the wires coming into the assembly because the circuit boards on those are known to go bad. I would lean towards the switch first. Hope this helps.

try looking on the fuse box, see if it is still okey, then replace if neccessary

yep bad ground in the dash

I have notice that this is a common problem. The socket most of the time goes bad, I don't know why but they just do. You can pick them up at any parts store for around 5.00 each. If you don't have a volt meter and ground straps to test it right, then I would try changing the sockets out. Quick and easy. Let us know how it goes.

there all on the same fuse check the fuse the look for a wiring short or water in the tail lifg lenses

brake lights and turn signals work off the same curcit, it could be the fuse or the brake light switch !!!!!!

Look up under dash where brake pedal pivots, you should see a switch that is activated by pedal arm.

i would replace the brake light swtich first its more likly too go bad than the turn signal switch