Running Lights Stopped Working on Horse Trailer Towed by a 2003 Ford F-350

Question:

running lights and tail wont work on horse trailer. I have a 2003 f350 dieseal dually

asked by: Joseph M

Helpful Expert Reply:

Running/tail lights are on the same circuit on your 2003 Ford F-350. The likely problem is a blown fuse or relay associated with the running light circuit. Use the truck owners manual to find all the locations of the fuses and relays used for the tow package wiring. Checking fuses is easy but to check a relay the easiest thing to do is to place a known working relay in place of a possible bad one. If the function then starts working then you know it was a relay. I have linked a help article on troubleshooting wiring that should help.

expert reply by: Michael H