I am have trouble with the rear tail lights on my 02 2500HD. One appears to have the brake light on all the time and the other seems ok when I push the break they alternate. The cruise control doesn't work when the lights are on and my brake controller stays activated until I press the break pedal and then all lights on the controller go out. When I use my programmer to check the DTC's it gives a PO571 code but no other trouble lights come on. Can anyone help resolve this problem.