Let’s start here, you get in the truck and hit the brakes. Both brake lights work. Then you use either of the turn signals, both brake lights still work. You then use the brakes while using the left turn signal, say you are sitting at a light making a left turn. Only the right brake light will work after the signals are canceled. This will continue until you use the right turn signal without applying the breaks. It’s like something resets after that and both brake lights resume normal function. This will occur as often as you use the breaks and left turn signal together. I have verified this with a meter reading at the wires before the harness from the frame to the tail lights. There is no tow package. Both tail lights are new including harnesses and sockets