Dealer Installed 7-Way Trailer Connector Does Not Work on 2012 Volkswagen Tiguan

Question:

I purchased the genuine VW parts hitch wiring kit with Pollack 7-pole trailer socket only type sold for my vehicle for my 2012 Tiguan and had it installed after market by my local VW service center. I plugged in a Hopkins 7-pole to 4-pole adaptor and found that it will not work no coninuity at socket and it causes a bulb failure indicator message on the dash. VW is telling me that the 7-pole Pollack socket is wired for separate lights and that the 4-pole flat is set up for combinded lights and the two cannot be conjoined and the only way to get the adaptor to work is to purchase and install a separate-to-combined light wiring converter before the Pollack socket. Does this make sense? Will the Pollack 7-4 pole adaptor work instead since it is the same manufacturer or is it possible that VW simply wired my hitch harness incorrectly when they installed it? I am already in for $700 and dont want to spend more. Any insight would be greatly appreciated.

asked by: Vincent

Expert Reply:

It actually does not make sense because a 7-Way trailer connector also has combined brake light and turn signals so unless the adapter you bought is something out of the ordinary it is not the issue. The issue on many newer German vehicles is when you are towing a trailer with LED lights, the power draw is not sufficient for the OEM trailer wiring. What is needed is a special adapter, # C35FR, that adds extra resistance so you do not get the bulb out warning and the lighting on the trailer will work as it should.

They very well could have incorrectly installed the 7-Way. They would want to make sure the separate ground on the 7-Way, if it has one, is attached to a clean metal surface on the frame. If they hardwired in trailer wiring then they may have the wrong tail light wires.

Did your Tiguan come with a factory 4-Way?

expert reply by: Michael H