Technical AAnyone have a wiring diagram for a MKIV under dash AC unit?

Greetings! Picked up a MKIV under dash AC unit that I want to install, and as simple as this thing is I am not sure how it works or how it should be wired. I put up pictures of what I have, there is a brown wire and a black wire connected to something on the side (relay? Circuit breaker?) Brown wire looks to be connected to both the 12v side of the fans and one side of the relay or circuit breaker. If I put 12v on the brown wire and ground to the black wire nothing does anything. If I put 12v on the brown wire and put the ground to the fan case I can control fan speed from the left side AIR knob. Right side TEMP knob I do not know what it does, if I turn it one way it just turns off the fans.
Unit is not in the greatest shape but if the evaporator is ok I would like to try it.
Does anyone know how I should be wiring it and how the TEMP knob works? TIA

 

The square thing with two wires is a circuit breaker. That's where power goes into the unit.

There should be a fan speed switch, and a temperature knob. The fan switch gets power into it, then sends it to the blower motor. The temp knob is a thermostat switch that gets power and sends it to the compressor clutch, when the unit is too warm. As you run it and the temp goes down, then the thermostat switches off, the compressor shuts off, and it gradually warms up...then it turns on the compressor, etc.

this diagram I found on the internet is close...but the circuit breaker on yours is where "12v fused from ignition" connects.

 

OK, so in my pictures then the black wire should be the 12v in then? It looks like the brown wire runs inside the unit. so that could be the wire to the temp switch. I will have to put a meter on it and see if it works that way, thank you for the diagram!

 

There should be a power wire that goes in, to the switches. And a wire that comes out, to the compressor. Usually it helps to pull the cover off, so you can verify that the power wire goes to the fan switch, and the compressor wire comes from the temperature switch.

 

I use the exact one in my 64 elky and works great.even bought a spare.hot in and hot out to the binary or trinary switch.

 

I have the same in my 52 GMC. There is one incoming hot +12v supply, and then the internal fan and temp controls and wires inside, then a +12v coming out that goes to your compressor (best through a pressure safety switch). The Mk IV unit grounds through the case. Just the two wires you need to worry about.