Troubleshooting Trailer Brake Lights Not Functioning on Tekonsha Harness for 2018 Volkswagen Golf

Updated 05/26/2021 | Published 05/24/2021

Products Featured in This Question

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

(49)

$62.84

Hook Probe Circuit Tester

(62)

$13.33

Question:

Hello I have the 118730 tekonsha wiring kit my vehicle is Golf sport wagen 2018 my problem is that I have no brake light flasher only the parking light that lights on the trailler can you help me tank you

asked by: Ghislain

Expert Reply:

First thing you should do at this point is test the 4-way of the wiring harness with a circuit tester part # PTW2993 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached.

If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. That would mean that problem is either due to a ground issue or a short issue.

Make sure that the trailer side connector 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.

If the problem is on the vehicle side then I would first recommend you double check how the harness is installed on your vehicle, sometimes just unplugging the connections and replugging them back in fixes this issue.

expert reply by: Jameson C