1972 Deville No HEAT/AC
 

I'm helping a buddy with a restore of a 72 Deville with 17K original miles. He told me about five years ago the heat and AC gave out. I checked the fuse and see that it is OK. I know that the heat/ac switch connects into a programmable control module. Both are expensive repairs. Is there a way to test which componet is bad? The switch does nothing except move the va***n flaps in the heater box. No heat, no A/C (does not engage ac clutch). no fan, no nothing. Moving the temperature thermostat does nothing.
The car is a living history do***ent. His other toy is a 62 Buick Electra 225. Both are testimony that AMERICAN Cars ruled the road!