I have a 99 GMC jimmy I just bought a few months ago. Everything worked fine on the truck. But I've noticed that my brake light comes on when I apply a small amount of pressure on the brake.
The brake light switch may have a bad contact in it, their about $15 Here's the oe part number 15128745
Looked at it. Didn't disconnec . And lost tail brake lights completely... But third brake light still works. Could this be a short????
If third brake lights work there must be a broken contact to the lower lights. check light harness connection under the truck at the rear.Check for ground wire at the frame.