[84t0y]

2003 chevy all lights work except brakes lights, including the third brake light(on cab)

what ive checked
bulbs, a couple were burnt out but i replaced them, didnt help
fuses, checked and they look good.

really not sure what to check somebody told me it could be the brake switch but i dont even know where that would be.

 

[KWTMECH]

Do the emergency flashers work?

 

[HAPPYJOHN]

Should be under dash, roughly lined up with column, has a plunger
that contacts brake pedal arm.

 

[GMGuy]

Check the connector. On the fullsize vans around that time the connection from the weatherpack connector to the lamp base would corrode. Specifically the ground wire connection. Wedge something onto the brake pedal to turn the lights on and 1)check the harness connector at the rear for voltage on the brake/turn wire. 2)if 1)checks out, then wriggle the wires on at the lamp and see if it'll come on. If it flickers, you've found your culprit.

If your handy with a soldering iron, you can ******* repair it. Remove the ground wire from the weather pack connector, take wire cutters and cut away the housing plastic on the ground pin, and solder the ground directly to what little stub of good contact you find. Seal with silicone.

Alex.