I keep blowing a 25 fuse for my trialer turn, tail, and 4-way under the hood of my F-450. The connection was broken off in the truck connection with wires crossed. I checked, and replaced the connections, but the fuse keeps blowing still, what could cause this?
Disconnect all the wires going for the trailer connection. Then put a new fuse in. If the fuse does not blow then the problem is the wiring to the trailer connection. Check each wire with a static light and mark what each one is for. Check each wire for the tail lights, the brake lights label each one with a piece of tape. Then using a 12 volt battery and a jumper wire check the wires on the trailer. Use the tongue as a ground. From the positive side of the battery touch each wire and mark what lights go on when touched when connected from the jumper wire. Then match up the wires from the truck to the trailer. Usually the white wire is the ground on the trailer.