Troubleshooting Boat Trailer Wiring That Blows Fuses

Updated 03/28/2018 | Published 03/26/2018

Question:

Ive got a boat trailer and keeps blowing the fuse in my truck Ive replace the fuse and all the light come back on . Last most of the day then boop they go out running light r out blinker work and brake light work when used any atvice on were to start?

asked by: Caleb

Expert Reply:

There are a few possibilities for your truck fuse blowing after connection to the boat trailer.

It is possible, but maybe not likely, that the total number of clearance/marker/tail lights on the trailer, which all use the same circuit for power, require more current than your truck wiring can deliver. If the trailer's lights are the more power-hungry incandescent type this is more likely than if there are efficient LEDs.

There could also be a short somewhere in the running light circuit; worn or cut insulation or a wire that rubs against the trailer frame could short that circuit and blow the fuse. This could be on either the truck or trailer side. Sometimes such problems only occur when driving, when vibration and motion cause the wire to short.

You could even have a corrosion problem within one of the light housings that is causing the short and blown fuse. Clean out any such corrosion and apply dielectric grease # 11755 to keep moisture out.

I suggest carefully inspecting the trailer wiring from the connector all the way back along the full length of the wiring and to the lights. Look for any signs of damaged wire, wires rubbing, or anything that looks questionable. If only the running lights fail then focus on that wiring from end to end.

expert reply by: Adam R