This was from the manual for their "Smart series" for a 67 install at least (what I was looking at for my car's controls):
View attachment 1716324861
Shows the compressor pretty much on all the time, which I get because you use it to dehumidify the air, but I rarely run my car at full heat. My factory heat only with only floor vents will make me sweat in the middle of winter if I run it at max heat, even with my leaky/non-existent weatherstripping.
I basically just want a heat/cool toggle switch so I can pick when I want the compressor to run since I would be wiring it through my Megasquirt to provide A/C idle up and to run one of my electric fans for better cooling. I don't want the compressor and fan running in the middle of winter if I want less than full heat. My plan was to just put a toggle switch on the compressor clutch line to be able to manually turn it on and off, easy enough.
I'm actually debating if I want to be really silly and control the box through my Raspberry Pi. I'm 99% sure the mode and temp sensors in the kit are just potentiometers of some variety. Whether they provide 12v or 5v back to the controller is the biggest question, but an easy enough one to solve with a multimeter. I'm half tempted to put a cabin temp sensor in the car and make my own automatic climate control where the Pi watches the cabin temp and commands the box to adjust accordingly.
I am curious to see how your engine side install goes though. I finally got a factory compressor for my older 5.7, so I was going to see about getting a non-crimped kit from them so I could make my lines the right size. I know I'll need some different vents if I want to do my radio idea as well, but those are cheap enough and I think I can 3D print some adapters to make it work if needed.