I'm adding an a/c to my 84 from a 86 donor. Do I need to add a high pressure switch or does the factory system have one. I installed the evaporator last year and don't remember.

I also can't find the wire to the compressor under the hood. Does it run off of the a/c relay behind the dash?

Any other tips to make this system a cold one?

Any help would be appreciated.

1984 X-cab 4x4, chevy one wire alternator, 22r, looking for mods