my break lights stay on.

Try disconnecting the brake switch by pedal and see if they shut off, if they do, it's the switch if they're still on, you have a short and will need to start tracing curcuit disconnecting harness plugs starting from rear lights

I believe that the BCM controls the brake light on your truck. The switch signals the controller that the brake pedal is depressed. You need to look at data stream for BCM and see what the BCM is seeing in relation to the pedal sensor

Under the bed where the wires attach, they can get worn and crack after awhile. Since brake lights work on a ground circuit, could be a bear wire touching ground.

Don't have any answers. Changed the fuel tank yesterday. Afterwards the brake lights came on and won't go off. Even without the keys in the ignition. So i replaced the brake switch. Lights are still on. I'm stumped.

Switch is not open closed switch on GM anymore, depressing pedal in itself does not trigger the lights. The switch attached to pedal is more of a relay than an actual switch. Too much computer control now, like simple analog wiring much better.

Can u reset the break light switch on 99 gmc 4x4 1500 my break lights stay on put new break light switch still on I can press pedal down and lights go off for second then back on help me fix it plz or sell it one

It’s brakes. I just go out and press lightly on the pedal. It just didn’t reset all the way

I thinking it may be the rear brake components are worn out and the brake release spring isn’t allowing the brakes to return closed.

can someone help me i have a 1987 gmc Sierra 1500 i have brake lights till i turn on my park lights and then i have no park lights or brake lights but have park lights in front i changed headlight switch and checked wires in column