Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Does the truck have any aftermarket accessories (radio, etc.)?
Any trailer wiring?
Double check the trailer wiring, then check wiring going to each taillight and front park lights. You will want to look specifically at the Brown wire at each light. Look for any chafing on this wire or any pinched areas.
It has to be a harness that is moving with the vehicle turning or perhaps is getting pinched as the body flexes. Removing the lights and inspecting the harness should be the next step.
Yes, just let me know tomorrow or whenever is most convenient for you.