Brakes lights only work when lights are on

[Aarondash]

I got a 1998 k1500. The lights all were just working fine. Now the right brake light doesn’t work. But when my lights are on it does work. What could that be?

 

[fancyTBI]

I got a 1998 k1500. The lights all were just working fine. Now the right brake light doesn’t work. But when my lights are on it does work. What could that be?

Check your grounds. There is a ground for the tail lights on the drivers side of the frame at the rear. I recommend removing them, cleaning them up, installing with a new shake-proof washer. Check the harness that is by the rear bumper, too. If you’ve got a trailer light harness connected to the existing tail light harness, it could be causing some issues. Usually they are so full of dirt and moisture that they degrade over time and you aren’t getting a good connection.