Right Turn Signal on Boat Trailer Not Working, All Other Lights Do Work

Question:

All other functions working. I have cleaned the ground and the connectors. Any suggests that will fix the problem? The trailer is a 1990 ez loader with new stop lights and has been rewrited.

asked by: Larry F

Expert Reply:

To isolate where the problem is the first thing to check is the vehicle side trailer connector. Use a circuit tester such as # PTW2993 to test the pin for right turn/brake lights. If the brake signal function works but the turn signal doesn't then it could be a blown tow package fuse on the vehicle.

If everything works on the vehicle then that leaves the trailer as the culprit. On a trailer the brake lights and turn signals are on the same circuit. So if the brake light is working then the turn signal should be too.

This does sound like a ground issue. 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, but not always.

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

Ryan

6/25/2020

Everything works on my truck. My trailer lights up when plugged in. When I press on brake only the driver side works on trailer and same with blinker. Is this a bulb issue on the passenger side or a fuse /connection issue

Chris R.

6/29/2020

It could definitely be a bad fuse under the hood. The brake and turn signals are sent along the same circuit for trailer wiring. Check your truck's owner's manual for the location of the fuse that's tied to the trailer passenger side turn/brake circuit. Replacing it should hopefully resolve the issue.