72 demon A/C electrical help

I have finally started my 72 dodge demon resto after years of storage and putting it off. it is a factory A/c car I took the motor and dash out today and noticed there was no wiring to plug into the A/C compressor, and also in the dash there is a selector switch vacuum pod with lines and a 5 prong plug but nothing pluged in it and nothing that I found in the harness that would go to it. on the evap box it looks like a resistor or fan speed control with no wiring to it. this is my first mopar resto so my question is is there a harness that is missing that is separate from the dash harness or has someone changed the harness in the past. any help would be appreciated thanks