Trailer Connector Testes Fine But Trailer Lights Dont Work

Updated 05/13/2021 | Published 05/12/2021

Products Featured in This Question

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(42)

$63.92

Hook Probe Circuit Tester

(61)

$13.33

Question:

I have had this installed and the tester said that it was working correctly, but when I connect the trailer, nothing, no lights brake or turn single. I had the t-1 installed after 2 curt units didnt work. any Ideas? thank you

asked by: Kevin G

Expert Reply:

If you've used a circuit tester like # PTW2993 on the pins of the 4-pole trailer connector provided by the # 118749, then the wiring problem exists on the trailer. In order for none of the functions to work, you probably have a bad ground connection. The ground wire from the trailer connector will typically ground to the trailer tongue. Make sure this connection is secure and made to clean, non-rusted metal. If not, sand the grounding point down to bare metal and install a star washer between the ring terminal on the ground wire and the trailer frame. When the screw or bolt attaching the ground to the trailer frame is ran down, the star washer will get a good bite into the trailer frame, ensuring a good ground connection.

I've linked you to a help article that runs through the process of troubleshooting, as well as to a video showing how the circuit tester works.

expert reply by: Mike L