Just an update, I did my trailer wiring this past weekend, using 000 979 227 (2.5mm or ~13 ga.) wire to add a new circuit to my fusebox. I spliced it to 12 ga. primary wire using Posi-lock butt connector.
The hardest part of the install was getting all the trim out of the car to run the power wire. I broke a lot of clips in the trunk area, trying to remove trim pieces that ended up not needing to be removed. Me not owning the Bentley manual, I'm not sure if I would've done a better / more efficient job if I did own it. For all the write ups here, there aren't very clear ones on these type of details, and since it took me about 6 hours 'til it was all said and done, I didn't take photos for a good write up, either. So I guess I dropped the ball there.
The Posi-tap connectors to "splice" into the vehicle wiring worked, but I can't believe how fine gauge the VW tail light wires are!
All put back together, when I started the car, I got a "FAULT - STABILIZATION CONTROL (ESC)" warning, and the steering wheel, tire, and swirvy car light were lit up on the instrument cluster. But as soon as I started driving (literally less than 10 ft.) they all went off, and a code scan at AutoZone revealed NO fault codes.
Two days later, I had the opportunity to tow my Uncle's utility trailer to move two upright freezers (one at a time), and some stumps we pulled from the yard. The wiring was done correctly; running lights, turn signals, and brake lights all functioned as needed. The family truckster did very well towing - I barely "felt" the trailer, but I was overly cautious (mainly because of the tall aspect of the freezers - we needed to use them immediately, so couldn't lay them down).
So there's my experience for the record.
