You are right about the thin cables that supply light to the switches and sorry I don't know how they work but on a 86 420SEL that I was parting out, once I had removed the center console, the radio and the climate control unit I saw the connections hanging right there. It was one main cable that branched off into several little ones. I really believe it was driven by a light source (bulb). Not sure if you really need to remove all these parts to get to it, but its right behind the CCU.