Trailer Left Turn and Brake Lights Sometimes Do Not Work on Trailer Towed by 2014 Kia Sorento

Question:

2014 kia Sorrento tow vehicle, 1962 Shasta airflyte camper. hooked up to come home a week ago from camping and noticed I had no left turn or brake. replaced bulb when got home...no fix. took back to storage for a week...got it out last Saturday..hooked up and all lights worked fine. came back today and left turn and brake are gone again. cannot pass VIN inspection without lights...help!!! 4way plug on both.

asked by: Rob S

Expert Reply:

This is a textbook example of a bad ground connection. 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