Troubleshooting Trailer And Tow Vehicle Wiring When Trailer Lights Are Malfunctioning

Question:

Jayco Tent Trailer - left turn signal turns on all lights, Right turns on nothing and brake turns on everything. What could be wrong?

asked by: Brandon B

Expert Reply:

First, I recommend using a circuit tester like part # PTW2993. Have someone run through the functions while you test the pins on the trailer connector of your vehicle. If everything checks out, you will want to move to the trailer and check it out.

It sounds like a ground problem on the trailer is what is causing your lighting problem. You will want to check that the white ground wire on the trailer's connector is properly grounded to a good, clean area of bare metal on the frame.

You want to make sure all the trailer lights are properly grounded. If the lights are grounded through the mounting hardware you will want to make sure you have a good ground.

You can also use a 12V power source and test the connector on the trailer to make sure they match the vehicle connector.

expert reply by: Jeffrey L