Right Turn Signal Not Working on Trailer Towed by 1998 Ford F-150 4x4

Question:

I have a 1998 f150 5.4 4x4 I have 7 way wire in the back I dont have no power to the green wire which is my right turn signal I traced the wire found the box nothing is bad what else is there to do

asked by: Garry W

Expert Reply:

You will want to check the fuses/relays related to the tow package wiring to see if something needs to be replaced. Use the truck owners manual to find all the fuse/relay locations. The only way to test a relay is to use a known good one in place of a potential bad one.

If the circuit on the truck side connector actually has power but the trailer side right turn signal does not blink then it is likely a bad ground. But you will need to also make sure that the truck and trailer side connectors are clean and free of corrosion inside and out.

Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light.

Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal 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