96 Suburban AC not working

[The_KC_Kid]

I am a certified auto a/c tech, 3rd generation family owner auto heating and cooling shop. First, jumping the pressure switch tells u two thing, 1 the compressor clutch is still good, 2 the electrical system ( wires them selfs) are operating properly. The thing they dont tell u on the "a/c pro" advertising is that if ur having to add freon to ur vehicle, that there is a leak SOMEWHERE. When freon leaks out it also lets air in, when there's air in the sytem ur gauge set could show proper levels but u could only have 1lbs or freon and 2lbs of air trapped in the system. U need to take it to shop that has a A/C machine that will pull the system into a vacuum and get rid of any air and moisture in the system.

There are two things ALL 88-98 GM fullsizes are bad about. First thing is the a/c fitting on the line that bolts to the top of the compressor, it uses a rubber ball instead of a shrader valve and the rubber deteriorats over time and leaks. Second thing is the compressor seal itself. The original compressor that came on 95 and up (I belive 95 off the top of my head) use a multi piece comp housing that is pressed together when manufacturer and uses 3 big o-rings to seal the compressor itself. Easiest way to check if comp is leaking is look at and if there is oil residue ontop of the compressor, the o-rings have gone bad and its time for a new compressor.

Hope this helps u out and if have any questions just message me.