Troubleshooting Running Light Fuse on Vehicle Blowing with Trailer Connected Headlights On

Question:

My running light fuse blows when I turn the lights on with the trailer plugged in. Should I be getting continuity through the running lamp pin and the frame when I use my testor. It seems I have a short?

asked by: Joe N

Expert Reply:

Your trailer frame should work as a ground for your running lamp pin so that does not seem to be an indicator of a problem. Now if you can test voltage on the frame of your trailer when the running lights are on that would be an indicator of a short, but I don't think that's what you meant. Trailer lights typically ground through the mounting hardware and then to the trailer frame so it sounds like what you tested is normal.

What is most likely happening is that your trailer running lights are drawing too much current from your running light circuit on your vehicle so the fuse is blowing. The solution for this is to install a powered trailer wiring unit like part # 119250KIT that will draw the taillight amperage from the vehicle battery or convert the running lights on the trailer to LED which draws less.

I attached a link to a page that has all of the LED taillights we offer.

expert reply by: Jameson C