I am surprised myself, as I thought there would be, the previous owner had fitted a Pioneer stereo, so I'm unable to tell if there was a D2B cable connected to the Audio 10 headunit. I've been looking behind the headunit as well as in the door sill, but no D2B cable to be found. It is a pre-facelift (04/1999) model, so no steering wheel controls.

I have nothing connected on the C1 and C2 connector (yet), but if I understand things right, I need the D2B wakeup on C2 pin 10.