Troubleshooting Why Truck Has Running Lights But Trailer Does Not Have Lights When Connected

Question:

I have running lights on my truck but not on my camper thuiler what could be the ploblem.

asked by: Bernard K

Helpful Expert Reply:

You will want to use a circuit tester like part # PTW2993 and do some testing.

Have someone run through the functions on the truck while you check the pins on your trailer connector at the back of your truck. Make sure they are clean and free of corrosion, and that the ground is securely attached to a clean metal surface. A loose ground will cause all kinds of issues. You will also want to check the fuse panel and see if there is a towing fuse needed and make sure it is not blown or missing. If it is blown, you will want to make sure you fix any issues with the connectors or wiring to make sure it does not continue to blow fuses.

If you find you are not getting current to some of the pins, check the wires at the back of the connector and make sure you are getting current there. If not, you will need to trace the wires forward to find the problem and repair as needed.

If everything checks out on the truck side, you can then move to the trailer side. Check the connector for corrosion or any signs of damage and fix as needed. Then you can use a 12-volt power source and test the lights on the trailer as well. Check for loose or damaged wires and ground wires and repair.

expert reply by: Jeffrey L