Hi Paul,
This is kinda long...first the link to some photos...
A/C switched photos I wired a relay and switch into the A/C circuit behind the HVAC selector panel. (The first switch in the pics is not the one I ended up using.) I tapped the GREEN/red wire for a power source for the relay. The GREEN/orange wire is a ground wire for the A/C clutch and that wire is cut and now connected to and operated by the relay. The switch I used was from a 1981-2 Datsun 200SX. The photos should help. The a/c switch will run the compressor only when it is depressed and the selector knob is in one of the four a/c positions. The light in the switch, however, will come on anytime it is depressed and the selector knob is moved to any position other than "off". On the 1981-2 Datsun 200SX switch, there are three wires, the two upper wires are to the contacts that will operate the relay and the third lower wire is for the light. The wire for the light goes directly to ground along with the ground for the relay. As I recall, it made a difference in the operation of the light, which wire from the switch was wired to the GREEN/red "hot" wire. I don't recall which one, sorry. You will really like the switched operation...it's great!
...Ed
