[dodis]

Hello,
Retrofitting engine with edc16cp34 to older car, have questions about cruise control.

Taking for example audi b7, c6 or PQ car.

We always have one wire from ecu to steering wheel module.

1. Does cc controls with this wire, like LIN, or its just enabling cc, and signals  from steering wheel module to ecu are sent via powertrain can?

2. If everything controls via this wire, what kind of signal it is ?
3. If this wire just enabling cruise, what signal does it sends for it ?

Thanks.

[Versus]

This 1 wire enable cruise function in engine ECU only. Cruise enable and disable by "shorting this wire to GND".

[dodis]

Are you sure that enables by ground ? It seems  over positive. And everything else over can. 
I compared wiring diagrams:
1. A4 b7 with BDG engine edc15vm+  enables by steering wheel module
2. Any older edc15vm+ enabling by positive to the same ecu pin
3, A4 B7 edc17cp enable by the same steering wheel module as edc15.

So it seems positive.

And for CAN control will need to grab can ID's and build emulator.