Where is the ford f350 trailer fuse located?

There are two fuse boxes in the Ford F-350. The one in the passenger cabin houses the trailer fuse. If You look near the brake pedal on the driver side, You'll find the access point. The one for the trailer is a 20 ampere rating. It should be number 6, but You can verify this by looking at the diagram on the inside cover of the box. Your vehicle might have a plastic fuse removal tool inside one of the boxes. Otherwise, You can use Your fingers or pliers. To replace the old one with a new one, pull the blown one straight out of its housing. Make sure You have a fuse with a proper ampere rating and gently snap it into the empty spot. If You are still have problems, then You might have an issue with the wiring or electrical system.