72 Cutlass. I noticed my compressor is kicking on when I put the selector to heat. Is this right or is the wiring messed up somewhere? Compressor comes on also when on def, and norm and max. The vent setting is the only one that does not run the compressor.

 

You may have something a little out of adjustment on the control head. DEF, NORM & MAX should engage the compressor. All other positions should not.

I think the CSM shows how to adjust that master switch.

 

I've been looking at the CSM on Wild about cars. I'll have to study it a bit more. Maybe look at a wiring diagram.

 

Still stumped on this. Does the vacuum control when the clutch engages on the compressor?

 

THere is an electrical switch in the control head that switches the compressor - all mechanical. There is also a main system switch that also controls the fan.
The vacuum is only used for hot water valve and air door control.