grober
MB Master
Meant to post this a while back. Came across it while researching a towbar for an Audi Allroad. Its a Westfalia Towbars site. First locate the tow bar you want then look for the installation instructions/wiring details. Site is not easy to navigate but theres a lot of info there. Westphalia are OEM for AUDI and MERC I think?
http://www.westfalia-automotive.de/e_frameset.htm
http://www.westfalia-automotive.de/e_frameset.htm