yes running the 2 wires did take an hour or so and I googled the J519 unit and got a screen grab so I could tell which is the correct connector to plug into since it's difficult to see under the dash. As long as you've got the correct connectors to plug into the harness it's not that difficult.I'm not sure. There were always various issues using wiring harnesses as shortcuts on either the Mk5 sedans or hatchbacks.
You've got the correct coding for Bytes (not bits) 09 through 13. Remember that the farthest-left byte is 00, and you have to count up from there -- so Byte 09 is actually the 10th one over. Yes?
In any case, the guaranteed way to get the lights to work on the Rabbit/GTI the way they were designed, is to run the 4th wire on each side. Pain in the ass with finding the correct connectors, but the worst part is working under the dash.
Marek has great advice and write-ups on here about redoing the lights.