Truck Blows Fuse When Connected to Trailer

Question:

I have a trailer that only when you hook the hitch up will blow fuses. trailer has been tested by a buddy tester and other trucks and there is no problem. same if the truck that is blowing fuses is hooked to other trailers does not blow the fuse. trailer is a pintle hook system and the hook is worn smooth on the bottom. i have tested the truck and trailer multiply times and i can not replicate the issue with jumper wires touching the hook and hitch. nor does adding a ground fix the issue. only when pintle hook touches the hitch. f350 . i have cleaned connectors multiple times and have tried different wips. all wips have been tested and work fine. i wonder if the ground down pintle hook has anything to do with the situation. any input would be great.

asked by: James P

Expert Reply:

This is a really odd issue you have here with the fuse only blowing on that truck and only when it's hitched, and what my colleagues and I think might be happening here is that there that there is a short on the trailer due to an exposed wire on the frame. That is energizing the frame and when you are connecting your hitch it causes the fuse on your truck to blow.

Our best guess is that the truck this is happening on has a lower rated fuse than other trucks you have tested, so I would look for any type of frayed or otherwise damaged wire somewhere along your trailer frame, and replace as needed with # 10-1-1 wire.

expert reply by: Kyle S