when i use my trailer at night, with my headlights on, i am blowing the signal light fuse on the truck when i go to use the signal lights. works fine during the day.

someone suggested uping the amp of fuse, but i think i need to take care of the problem the right way.

bad ground at trailer plug???

several yrs. ago I purchased a brand new truck, hooked up my trailer and blew fuses every time.   there was some sort of larger (master fuse thingy???) missing from under the hood.  once that was installed everything worked fine.   don't know if your problem would have the same solution but it was an easy fix.   good luck!

If you have a chronic, momentary problem that isn't easily resolved, NAPA sells automatically resetable circuit breakers, that fit all standard automotive fuse bases. They are available in most amperage ratings. As soon as the fault clears, the breaker will close and repower the circuit.

The installation of a larger fuse can damage the circuitry or components.

Gard