Well unless something in the tail light (like a circuit board) is bad then I would say warranty the stop light switch first as that is all that turns on and off the stop lights acording to the wiring diagram for your truck. I also need to ask if you have the tow package with taillight converter?

Answered by racefan966 (expert)
4,893 answers provided

Improper adjustment of the brake switch can cause the problem as well. Check the pedal for a missing stopper for closing the switch.

Answered by KHLow2008 (expert)
40,333 answers provided