Wire Functions On LED Trailer Not Working Properly With 2004 VW Touareg V8

Question:

I have a 2004 VW Touareg V8. Factory hitch and trailer light wiring. Here is issue. I use a 7-pin round to 4-pin flat adapter to tow boat trailer. Directional and hazard lights work but brake/tail lights do NOT. I am told this is due to an incompatibility between Touareg software and LED/incandescent trailer lights. I do not know if this is really the case or just dealer-speak. Do you have a solution? Thanks.

asked by: Erin D

Expert Reply:

I think a simple adapter may solve your problem. Since your trailer with LED lights has a 4-Way flat connector, you will need the 7-Way to 5-Way and 4-Way Trailer Adapter for VW, Audi and Porsche Towing Trailers with LED Lights # C35FR. This adapter has load resistors that provide additional power draw so the vehicle thinks there are incandescent lights on the trailer.

If the adapter doesn't solve it, there is most likely a wiring issue. I've attached an article to help you troubleshoot, but I highly recommend using an incandescent circuit tester like # PTW2993 to test each wire function. I've attached a video to help.

expert reply by: Jason S