Trailer Wiring Troubleshooting on 2015 Golf SportWagen

Updated 04/22/2016 | Published 04/20/2016

Question:

Hello, I have installed this harness yesterday. Apparently there are no issues shown in the system, however the testing probe I have is showing problems. The probe includes three LEDs: TAIL, LT., RT. which matches the wiring of white, brown, yellow, and green. In any case the test results show that - Left turning signal test as expected. - Right turning signal shows nothing on the probe. - Tail lights light up the RT. led instead. Had I been slicing cables myself I would have reviewed the connections myself already, however since this is a plug and play harness, at least from the signaling point of view, something seems wrong.

asked by: Robert T

Expert Reply:

Use your circuit tester on the Right Turn input from the vehicle wiring harness before it reached the taillight converter. Activate the right turn signal, you should see power on the green wire. Then, check the green wire on the output side of the converter, that leads to the 4 pole trailer connector. If you have power entering the converter, but not leaving it, the converter is bad. If there's no power entering the converter, then check the T connection where the harness plugs in to the vehicle taillight circuits. Make sure those connections are secure and the connectors are locked. Check the pins in the connectors, making sure they aren't bent.

Please check what I mentioned above and let me know what you've found. I'll also link you to an FAQ article about trailer wiring troubleshooting.

expert reply by: Mike L