Hello - hope someone can help with this. I have a 2012 Chevy Traverse LTZ with towing package and I do not have any lights in the rear except my backup lights and my top brake light bar. The directionals do not flash and the brake lights and taillights do not light up. This is on both sides of the vehicle. I am thinking it is a fuse or relay but not sure which one or which panel or even where to start looking on this. When I connect the trailer tester, I have all the lights on the tester working but still nothing on the vehicle itself.