Why Would Going with Larger Fuse in Tariler Wiring Cause it to Burn Up

Question:

We just replaced the Trailer harness on a small ATV trailer we have a few weeks ago. Went to go plug it into the truck today and noticed the wire harness is all burned up. Wondering what the problem is. We did replace the fuse for the trailer lights in the trucks engine bay fuse box to a higher amp fuse due to the boat trailer we have burning the fuse out every time we took the boat out. Not sure if that has anything to do with it but thought that should be inputted into the conversation.

asked by: Jeff Z

Expert Reply:

The higher fuse you installed is the reason the harness burned up. The rating of the fuse is designed to kill the connection if a short is present that would cause damage. By going with a higher rated fuse you essentially allowed the connection to stay in tact beyond the amperage rating of the wiring so it ended up burning itself.

The fact that you were blowing the properly rated fuse indicates that you had a short or were overdrawing the harness which should have been what was addressed and taken care of. What you'll want to do is go over the wiring of your trailer looking for any cut or exposed wiring and fix as needed to take care of the short before reinstalling new wiring.

expert reply by: Jameson C