Troubleshooting Trailer Wiring that Intermittently Works On Trailer While Towing

Question:

i just purchased a hitch and wiring harness for my truck, had it all installed at a local shop. When I went to pick up my new camper, plugged in to the camper and the lights worked fine. Once I started traveling a few miles up the road, I noticed the lights flickering, like there was a short in them. I stopped to get fuel and noticed they were not working at all. I pulled away from the pumps and started checking my plugs, it suddenly started working. I had a 4 blade flat and bought an adaptor to 7 blade. Does this ground by the trailer ball, because I backed up to the camper in the driveway without hooking up to the ball and no lights.

asked by: Ray

Expert Reply:

Trailer wiring can ground through the ball of a trailer, but since it's not a reliable ground and it can be intermittent (exactly like what you described), it is better to have everything ground properly through the wiring of the trailer harness.

The wiring of your trailer should have a ground wire that is securely run to an unpainted metal surface on your trailer. Improving this ground will fix the problem you described. You can also try running a jumper wire from each of your light assemblies to the main ground of your trailer.

expert reply by: Jameson C