[DoyleOil]

I figure this is going to be more of a wiring issue than a towing issue. I occasionally blow the 10amp fuse under the hood (large fuse box, the first 10a that sits by itself on the bottom row). However, tonight it blew on my way to hockey, then on the drive home.

I don't know how to even begin to see if its truck or trailer. sometimes its fine for months, and apparently sometimes for a few hours. Possible ides on what may be causing this?

 

[baseballfanz]

If it never does it without a trailer harness attached than more than likely it's the trailer IMO.
Could be a wire that's only shorting out here and there so maybe look for a slightly expose wire
that's shorting out maybe with movement of the trailer.

 

[DoyleOil]

I will have to pay attention to see if it is ever blown out before I plug in the trailer, i cant remember off the top of my head if it ever has been. Good call on isolating the problem!

I have a feeling its the trailer, but its an enclosed one so access to the wires isnt quite as easy. Ill have to take some steps to track the issue.