Troubleshooting Trailer Wiring for Ford 150 4x4

Question:

truck had all lights working, hooked it up to camper and lights on camper worked until I turned on the headlights then the camper lights went out. I was testing the truck wires in the back when everything stopped working. Red fuse in the is not blown I tested it.

asked by: Susan P

Expert Reply:

First thing to do is use a circuit tester like # PTW2993 to check each pin function on your trailer connector at your rear bumper. I've attached an article to assist with function locations. It sounds like your system was overloaded and shut down. The change in draw with the headlights on is significant enough that a bad ground on your trailer or truck could cause the camper lights to go out.

If when you tested the system shut down, then you want to not only check the red fuse as you stated, but grab your owners manual and check every fuse and relay in your system that has towing associated. If the fuses are good and you still have no power to any of the functions, replace the relay. If you still don't have power you will need to trace your wires using the circuit tester to probe every few feet to find the short. Check the hot side of the fuse location to make sure power is even getting there.

Once you've replaced all fuses and relays and checked the system wiring all the way back, let me know and we can continue to troubleshoot. Depending on the model year, you may need to use a different connector for proper function. I've attached an article to help as well.

expert reply by: Jason S