Troubleshooting Left Side Turn Signal Not Working On Trailer

Question:

I have a 1999 ford f150 and my left turn signal wont work.the right side works i checked the fuse and replaced them took a light tester and tested them and it work but the back of the truck nothing for left turn

asked by: Pat

Expert Reply:

This sounds like a ground problem on the left side. I recommend that you first check the grounds on the left side. Trailer lights usually ground through their mounting studs unless there is an obvious ground wire. In either case, the ground will need to be attached to a clean and corrosion free bare metal surface.

You can also make sure that the main ground from the trailer connector is also connected to a clean surface and that the connector itself is free of any dirt or corrosion. Make sure to check the vehicle side connector too. If you find any loose connections, broken or frayed wires, those will need to be repaired as well.

expert reply by: Chris O