Avant trailer wiring

[swalkerman]

I have an 07 Avant 2.0 quattro that I would like to equip to tow a small boat trailer. I already have the hitch, and now need to install wiring for the trailer lights. I have a wiring kit that does not involve cutting into the car's wiring harness, but rather uses inductive sensors to provide power the trailer's lights. This should mean the car won't freak about about current imbalance or bulb mismatch. However, I need access to the taillight wiring harness somewhere inside the car, and I don't know where the wiring harness is located. I assume it runs along the roof and down each D pillar. If someone can confirm this, I would appreciate it so I know where to disassemble to find what I need.

I have the factory service manual so once I find the harness, I can figure out the correct wires to intercept.

Thanks!

[GOODBYNAAIR]

Not sure if this will help. I have used the info from this site on 2 OEM installs and they have been great.

etrailer.com/Wiring/Audi/A4/2007/ (https://www.etrailer.com/Wiring/Audi/A4/2007/C59236.html?VehicleID=200738075)

[swalkerman]

I finished wiring my car today, and owe a big thanks to lookaught for his method.

https://www.audizine.com/forum/showthread.php/243601-DIY-B6-A4-S4-Trailer-hitch-installation?highlight=trailer

I had to do a couple of things differently because my wire colors were nothing like what he had (B6 vs B7?), and my Bentley did not have the separate wiring diagram for the Avant.
I had to trace the wiring from the light itself back to the junction block and probing to make sure it was the right one. I was also able to get 12v power from a power socket on the passenger side rear side panel instead of running power all the way back to the front of the car.