05 Colorado brake lights stuck on with headlights

[DonnyDrywall]

Okay, So my buddy just bought an 05 colorado and like the title says, all three brake lights come on and stay on when the headlights are turned on. When the headlights are off the brake lights work normally. Could this be a faulty brake light switch?

 

[Sparky]

Is it just headlights or is it also with parking lights?

 

[DonnyDrywall]

brake lights stuck on with parking and headlights

 

[Sparky]

OK that makes a little more sense how that could happen as the parking light circuit is connected to the tails but not the headlight circuit.

I'd be looking at the harness connections at the tail lights. The parking circuit is backfeeding to a brake light somehow maybe due to a failed ground. If you hit the brakes with the lights off, do the front parking lights also light up?

 

[DonnyDrywall]

yep, front running lights come on when the brake lights. we will be inspecting the harness and adding extra grounds to the tail lights. thanks alot man.

 

[Mooseman]

Also check the bulbs. I once had one short out in the bulb where the filament post melted and shorted to the other.

 

[DonnyDrywall]

Oh man, I forgot about this post. We fixed it that day, it ended up being the trailer wiring harness was in horrible shape with some very shotty repairs. I removed the harness and all is good.