[Brandon Miller]

Have an issue with my 2002 1500HD. The headlights, taillights, and dash lights come on when the key is on. This is my headlights and not the DRLs. I changed out the ambient light sensor thinking that was the culprit. Issue was not fixed. Could a bad headlight switch cause the problem or should I be looking at something else?

 

[OpalLacod]

Could be a bad headlight switch, but then the lights would be on all the time, even with the truck off. Can you still turn the lights on and off while the truck is off? If so, the switch is probably fine.

Pull the DRL relay and see if they settle down. You may have a short from the DRL circuit powering up the headlight circuit.

 

[Brandon Miller]

Well after sitting overnight, it seems as if the sensor was the culprit. All lights are now working as they should.