Glenn Lyford wrote:
The fuse was the problem.

If it ends up being the trailer that blew the fuse, then you might
consider getting one of those trailer light converters with the built-
in self-resetting breakers. I burned out a few fuses and a few
converters before I threw this one in, and it's lasted about three
times as long as the last converter I had before that, and I know it
protected the fuses just the other week when my trailer developed a
short (maybe I'll run the next set of wiring in pvc conduit?). Even
if you don't need a converter, it might be worth it for the breakers.

I just bought a circuit-breaker that replaced the fuse.
I still keep spare fuses (belt and suspenders, ya know)