I'm not certain about the f4 fuse location but there is a fuse under the hood in a box behind the battery. I blew that fuse changing out the lights on my travel trailer.
I thought I had a wiring issue and after spending the money on replacing light assembly's I found the harness that connects on the back side of the seven pin plug had a bent pin causing no power to go to my right rear brake or turn signal.(brake and turn are the same circuit)