TDI JSW 2009 J519 prob?

Driving started out okay, then post restarting lost all left rear lights (left rear running, LR braking, left rear turn signal), license plate light, and rear door won't electrically unlock. Looking at the Bently Electrical Wiring Diagrams EWD-490, it would seem to track to J519, C/12, C/2, C/11, C/10, C/9, C/8. Do those letters/numbers refer to terminals on the J519, and is C a subunit of the J519 that can be replaced or repaired?

One caveat, over the weekend, I was trying to install the Westfalia wiring harness (321 600 300 107) for one of their hitches, but other than connecting to the ground on the left rear wheel well, didn't connect anything to the electronics in the front end, and as I said, I'd driven the car without the electrical failure, since bringing the wiring from the rear of the car, to the front.

Any suggestions as to what I should do next, would be greatly appreciated.

thanks,
Jim

Fast forward many years later. I have the same problem on my 2011 JSW. Swapped the J519 but it did not help.