An issue on my '02 S6 Avant (Symphony II) - radio display on cluster is gone (everything else is fine) and the radio shuts off after an hour - like it doesn't know the ignition is on. I'm assuming (always dangerous on an Audi) that it's the CAN-bus signal to the head unit that's gone. So, which wire worked itself loose? Any quick way to check?

Thanks..

Should be tiny orange/lilac and orange/brown wires in the red 20 pin connector (the one which also has the CD changer and amp wires).

May have also worked free from the instrument cluster for some reason, although less likely.