Troubleshooting Utility Trailer Lights That Dont Work with New Trailer Wiring

Question:

After a year of not being used, I hooked the utility trailer up and all the lights did not work. I have a 5-blade to 4-pin adapter Hopkins 47345 4 Wire Flat Adapter on the car with testing lights that show the adapter is receiving power. I hooked the ground that was originally grounded to a screw on the trailer directly to the negative battery terminal on the car. Still nothing. I bought a new wiring kit and rewired the utility trailer I wanted to do it anyway. Pretty sure I wired it correctly. Still nothing. I suspect the ground but I am not sure why it is not working.

asked by: Samuel R

Expert Reply:

If you are getting the correct lights with the Hopkins # 47345 tester on your tow vehicle and you have rewired the lights on your trailer then the problem is likely a bad ground just as you noted.

Check all of the ground on your trailer and vehicle. Be sure that they are securely connected to a clean, bare-metal surface as even some paint can cause issues. Since the adapter that you use had LED lights for the testing it is possible that the problem is on your vehicle. LED lights use up hardly any power at all so there could be a major ground problem on your vehicle but a trickle of power is getting through.

Let me know if this doesn't fix your problem and I can help you troubleshoot further. A helpful article has been linked regarding troubleshooting trailer wiring for you to reference.

expert reply by: Jon G