How to Install Ground Wire To Trailer Connector on Utility Trailer

Question:

I have a utility trailer, the wiring harness for trailer only has 4 wires. 2 wires go to left light 2 to the right light, its grounding through the hitch and ball. But it keeps blowing the truck fuse, when in the morning when its damp out or when i hit bumps it blows the fuse. Ill change the fuse and itll work for a day or two. Eventually itll blow the fuse. The running lights will still work, but no brake lights or turn signals.. How do i add a ground wire?? The old wiring harness had 5 wires, 1 for the ground mounted to the trailer. I dont know how to add a ground wire???

asked by: Michael T

Expert Reply:

Grounding through the ball doesn't work well, as you've found. If the current harness doesn't have a ground circuit, the wiring must be fairly old as it's pretty typical for a trailer connector to have a ground circuit. The fact that you're blowing fuses leads me to believe you might also have a short circuit in one or both your turn signal/brake lamp circuits.

You'll want to replace the existing wiring harness on the trailer. This is pretty simple to do, and will only take an hour or so at the most.

If a 20 foot length from the tow vehicle's trailer connector to the trailer taillights will be long enough, use # HM48240 or if that won't be long enough, use # HM48265 for 30 feet. Wiring clips like # CE16867A will help keep the wiring runs neatly secured to the trailer. I've linked you to an installation video which shows how wiring harnesses of this type should be installed. I've also linked to a trailer wiring help article.

expert reply by: Mike L