My AC will not turn on

Have it checked for pressure normally when it wont' run it's low on pressure and this si a R12 system so suggest switching to R134. You probably have a leak.

We have no diagrams of this it's just to old. I do have a 1976 ford manual which will be similar. This system runs off of vacuum and electric and one of the things that made this system not cool was no vacuum to the water shutoff valve underhood. Or the vavle went bad. There is a compressor clutch switch at back of control head that mmay or may not being applied by contorl head check behind control to see if poer is coming in to swith because if it is then it's a switch problem If i'm right the blower switch feed the clutch switch so if one is gone the other won't work. There is a fusible link on the starter relay to protect the a/c it should be a 16 guage fusiblelink however I don't know what color it is it could be yellow orange or brown a test light wold be all you need to check it with pushing test light to oppisite side of link. They are availabe at auto parts Other than that due to the age of htis truck you'll hav eto find an electrical manual for thatyear for specific color wire

The control head is in the dash the part that you turn the a/c on and blower on but check the fusible link on starter relay first and no I can't post apic from that manual