Oh boy, where do I start :confused2: I went through this ordeal with my T-reg 2 years ago and it was a bit daunting to say the least. I HIGHLY recommend that only allow a VW dealer to wire up the brake controller or a VERY REPUTABLE RV shop who has wired up AT LEAST 2 or 3 in the past few months. Let me save you, or rather the installer, a big headache. Following is the wiring guide to match the color codes for most brake controllers to the T-reg wires in the connector housing.
The cavities on the T-regs connector housing are
numbered and the connector can be connected to the brake control as follows:
Wire position...................Vehicle Wire.......................Brake Control
in connector.....................
Color ..................................
Wire Color.................
Function
1......................................Brown....................................White.......................Ground
2......................................Red/Yellow.............................Black..........................12V
3......................................Black/Red...............................Red .....................Brake Signal
4......................................Blue........................................Blue......................Trailer Brake
You can also ask your VW service manager to contact their VW tech support for the wiring diagram to confirm this info. LOL
P.S. I just found out TODAY (the hard way :anger: ) that the Tekonsha Prodigy®, or Intella-Stop Ultra equivelent, brake controller
http://www.tekonsha.com/prodig.html does NOT work on 2005 or later T-reg models (2004 okay). Apparently these brake controllers cannot compensate for the contant low voltage going through the brake wire and they constantly apply your trailer brakes even when ACCELERATING - NOT GOOD! :confused2: BEWARE OF ALL FULLY AUTOMATIC HIGH TECH BRAKE CONTROLLERS. I strongly urge you to contact the manufacturer before installing one - save yourself the missery.