Troubleshooting Left Blinker Causing all Trailer Taillights to Illuminate

Question:

My 2008 VW Mk5 GTI has module installed with yellow to left tail light signal wire, green to right tail light signal wire, red to right brake light wire, and brown to right running light wire. When left signal is activated all trailer lights flash. When brake is depressed all trailer lights illuminate. Is there a different wiring combination required for a VW?

asked by: Jack W

Expert Reply:

Is it possible that the left turn signal was ran also to the running light circuit? Is this a new install? If you have a circuit tester like part # PTW2993 you should verify that the correct circuits are active on the input and output side of the box when all of the taillight circuits are applied. If the voltage is correct on input side but not output that would indicate that the box is fried and would need to be replaced.

expert reply by: Jameson C