Troubleshooting Brake Lights and Turn Signals Not Working On Trailer
Question:
Brake lights and turn signals don't work
asked by: Jerry
Expert Reply:
Since the trailer lights seem to work fine on a different truck, it's probably a safe assumption to isolate the issue to the new truck. It sounds like there is an issue with the turn/brake light circuit on your 7 pin connector similar to the # HM47295. I recommend starting by testing that circuit on the 7 way connector of the truck using a circuit tester like the # PTW2993. Odds are that you're not going to get any power on the circuit when you press the brake or engage the turn signals, so if that's the case, you'll want to trace that wiring back from the rear of the plug and make sure that they are connected to the correct lights on the truck.
This won't likely have anything to do with the brake controller, but is more likely tied to the actual wiring between the 7 way plug and the truck's tail lights/turn signals not being attached or damaged. I've linked a helpful article on wiring for a 7 way connector that you may want to refer back to for some diagrams, as well.
If you check there and everything is powered and undamaged, let me know and I can give you a few other things to have a look at.
