119190KIT for 2009 VW GTI

Expert Reply:

I am sorry you are having trouble wiring your trailer wiring harness on your 2009 Volkswagen Gti. It sounds as if you have made the proper connections on the vehicle if your system is a 2 wire system. From my research your vehicle should have a 3 wire system, (see link) and turn signals separate from the brake lights. Most European vehicles do. If the turn signals are separate you will need to find the stoplight wire behind the taillights and wire the red wire, that you grounded, to this wire. At this point you will need to use a circuit tester, item # 3808, if you need one to test the wiring. Start out on the vehicle side of the converter box and test the wires while someone turns on the various signals for you, without the trailer connected. Be sure to check all ground connections. If you have power to the red, battery, wire and the turn signals and brake lights all come on when activated then go to the 4-way connector and make sure each circuit works there with the taillights on and off. If everything is working properly there then you have a problem on the trailer side.

On the trailer side make sure the ground wire is attached to a good grounding point at the front of the trailer and make sure the lights are securely grounded to the trailer frame. Sometimes the license plate bracket is plastic and will not allow a proper ground. Once you have the ground wires connected then you will need to check each circuit outside of each light and inside the lights, taillights on and off, to determine that all functions are wired correctly. if you have a problem on the trailer side it sounds like a broken wire or a faulty ground.

expert reply by: Bob G