Hi Myles, The Mirrormatic lead wire is supposed to be hooked up to the "orange" wire that feeds power to the heater control lighting ( that little bulb at the top of the heater control unit) . This energizes the Mirrormatic when either parking lights or headlights are turned on. The answer to the other wiring question should be found in the Service Manual schematic. If anyone else has some relevant feedback, please pitch in. John