Only Right Turn Signal Works on Tow Package Wiring on a 2001 Ford Ranger

Published 04/17/2014

Question:

2001 Ranger - utility trailer with 4 prong flat connection Lights on trailer shorted out and evidentally messed up my truck setup. Tested at truck side of hook up: Rt turn signal works, tail lights and Lf turn signals do not. Ground must be ok as Rt turn signal works. Is there a fuse on the truck side of the wiring harness? If so where? Since truck wiring is encased where can I locate additional testing locations? All lights function on truck with or without trailer lights attached. Right now all lights on trailer are disconnected except primary tail lights - stop / turn lights. Any suggestions would be appreciated.

asked by: Loyd F

Helpful Expert Reply:

If the wiring harness on your 2001 Ford Ranger is a factory installed harness then there is likely fuses or even relays related to it. The best way to find them is to consult the owners manual for the truck. None of the aftermarket harnesses for the truck have fuses.

It could still be a ground issue on the truck. Just make sure that the main ground from the harness is attached to a bare metal surface, no rust or paint. Move the ground if you need to. If you cannot access the truck wiring and do not want to remove parts of the truck to access it then the trailer connector is the only place you can test. I have included a link to a help article for troubleshooting.

You will also want to make sure the truck and trailer side connectors are clean and free of corrosion. On the trailer side make sure the main trailer connector ground and the grounds for all of the lights are connected to clean and corrosion free bare metal surfaces.

If you recently installed a plastic license plate bracket between a light and the trailer frame, or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Michael H