MY BRAKE LIGHTS DONT WORK, THIRD BRAKE LIGHT WORKS, FUSE IS GOOD BULBS ARE GOOD AND NEW BRSKE SWITCH, TAIL LIGHTS WORK???

Do you mean your brake lights don't work? Check fuse first, brake light switch second, bulbs third. Could be a problem in signal light switch or wiring.

From That Light There Is Only 2 Wires , Trace Them Back To The Tail Light Connection - Most Likely A Split Wire Or Bad Connectio

The brake light side of the bulbs is powered by the brake switch and travels thru the turn signal switch.
If the third brake light works, I would guess the problem is in the turn signal switch.

The circuit to the taillight brake bulbs goes through the turn signal switch. Sometimes the switch can cause this problem.

If this third If the third brake light works then check the bulbs in the tail lights. If they are good then check for a fuse. I hope this helps!

I've worked on these the first drove me crazy. its the turn signal switch every thing runs thru these. head lights, turn signal, brakes. except the third brake light. it runs directly from the brake switch. go figuare

The third brake light switch works off a module for it is a sealed unit with a inverter that takes 12 volts beefing the voltage to 110 volts for the light emitting diode lights in it. It these terms you will need a new brake light switch located by the brake pedal

need to know if your third brake light up high is working or not.if it isn't,you need to check the brake light switch on the brake pedal with a test light,one side hot all the time,the other side should turn hot when brake pedal is pushed.

does the third brake light work when braking ? the bar on the rear window? if not replace brake light switch on brake pedel

I agree. My brake light dont work. Only the third brake light does. The running lights work but when i apply the brakes the rear tails dont light up.
I currently have this issue along with the signals dont work unless I bang the top of the steering colum. The hazard switch doesnt work either. If the signals dont work it makes this very quick clicking sound on the passenger side. I checked the fuses and they are good. The bulbs still work. The brake switch works cause the third brake light goes on. And seeing as I am having a problem with signals.....GM says I have to replace the switch in the steerg colume. Its a little box about the size of a cigarette pack. If you take apart the panels off ( right behind the steering wheel, where the hazard switch is) ...that is where it is located. Its plugged into the signal lever. Hope this helpa....Good luck everyone with this issue.