Need Ac Help 86 dodge ram 50

ok so i just bought this truck and it seems to me that everything was installed from factory.

The issues i have are that

there is no ac on/off switch on the hvac controls, no big deal ill add a toggle switch.

But none of the wiring is hooked up

i believe that the pressure switch is on the evap instead of the compressor, there is a black lead coming off the ac clutch, goes no where, black lead off of the evap that goes no where but i believe should be hooked up to the ac clutch??

one plug off of the evap, a two wire (green), which is the pressure switch? not connected to anything.
I know that the on off switch gets tapd into the yellow wires off the thermister control.

I guess what im saying is that i have an idea but i am not sure.

If anyone has a diagram of the ac unit, or ant help that would be great.

ps i also dont see any freon in the sight glass on the evap, how can i jump the pressure switch to bypass it, just to see if everything else works. if anyone has any links to retro fit to r134a that would be great too.

thanks guys:))

Bump

I got most of everything figured out.

Still looking for a ac diagram if any.

Manual section. You can use the first gen manual. It has everything you need.

ok got most of everything figured out. i found out that ac was a dealer install only. I dont believe my system was ever used before, I connected all electrical, hooked up a toggle switch for the ac to kick on. turned ac on by switch and clutch didnt kick on, out an ohm meter on the pressure switch and its at 650 some odd ohms. So the switch is off, jumped the switch to the get the compressor running and no cold air, i looked in the dryer sight glass and there is freon inside, but there is bubbles. I assume there is low levels of freon, But it has to go somewhere right? over 28 years and never being used shoud it still have a full charge? Any ways i bought a r134a freon recharge kit, and i think im going to replace the expansion valve and dryer for safe measures, Still not sure if they can go bad from just sitting. I also bought a ac gauge tester, going to hook that up and see exactly whats going on. If you have any answers to some of my questions that would be great. Keeping this thread updated to help other members diagnose there problems if they are the same as miine.

Ps whats the easiest way to get to the expansion valve, its under the dash correct?

yes it is on the high pressure line on the back of the box under the glove box. there were 2 different makes of a/c systems used by the dealers, both from mopar - lone star and frigette. expansion valve is in the same place for both systems. When recharging the system, either flush the system to remove the r-12 oil, or use ester oil with the R-134a refrigerant. PAG oil is the regular r-134a oil and it will react with the r-12 refrig oil and destroy the system. Since the system was never used, the seals in the compressor may have failed from being unused - a evacuation of the system under full vacuum will reveal that - if it doesn't hold a vacuum, you have bad seals. the box with the evap coil under the glovebox can be dropped down to access the expansion valve - be careful of the wiring for the a/c controller that is mounted on top of the box.

thanks for the reply and the info.

im going to evacuate the system tomorrow and give it a vacuum test. Ive had a hard time trying to find the right fittings for my high/low side adapters. Napa auto gave me the wrong ones, and autozone was oblivious to what i was asking. Going back to napa tomorrow to see if i can get the right ones. Which are 7/16s for the low side and 3/8s for the high side btw. ill keep this updated.

ok found the right size adapter but with my compressor the fittings where so close together that if you used one, you couldnt use the other. This is a problem if you want to connect a manifold gauge set. So i bought a new drier and installed it, this one came with a high side port which was great. After installed the new drier i pulled a vacuum of -29 of mercury and let sit for 2 hours no movement in the gauges at all. so i preceded to add 3oz of compressor oil, and 11oz of esr envirosafe r134a refrigerant, it also had dye in it. Well now everything works flawlessly. Compressor functions as it should, system is charged correctly and my ac toggle switch works as it should. I now have high 39 - low 40s air. Anyone have any questions ill be glad to help you if i can.