Sounds like a bare hot wire on the trailer's wiring harness that's
occasionally shorting against the frame, or against a ground wire. Hard to
troubleshoot. A new trailer wiring harness is pretty cheap and fairly easy
to replace.

"BIG FISH 2006" wrote in message
...
I have a 1998 GMC Sierra pickup 4x4 350 Vortec, and I keep blowing a
fuse when I tow my boat, it's the number 15 that controls the das and it
also runs the trailer lights. Anyone ever had this problem before? if so
how can I troubleshoot it.