GRA in B4: Another Case?

Hello everyone...

Unfortunately, I have to start a new thread again, this time about retrofitting a speed control system (terrible word...) into an Audi 80 Avant.
I've installed the steering column switch and now I'm looking for the connection to the electrical system. Since there wasn't a connector behind the steering wheel, I went to the dealership to ask about the wiring harness and the location of the connector. The answer I received wasn't very helpful: 'The wiring harness needs to be custom-made, and we can't tell you where the connectors are located...' Although it has been reported before in this community that a wiring harness needs to be created, I can't quite imagine that...
Okay, so here's the thing: I don't have the wiring diagram, and I have no idea where I would even run any custom-made cables. Maybe one of you could help me 'find' the right information, or give me the corresponding part numbers that I can show to the people at Audi...

Thank you very much.

Hello, it's possible that your engine control unit (ECU) is not configured for GRA (presumably referring to a specific feature or system). I'll check on Monday to see what's possible.