i bought my 1995 blazer 2 years ago when i bought it the previous owner told me the a/c just needed to be recharged because they replaced the compressor the fall before, i believed him since it looked new. i refilled it and it worked great. last summer it stopped working and i have not looked into until this week. when i turn the a/c on the compressor does not engage. so i switched the relays and it didnt do anything. i checked the presure with a quick check gauge i got from auto zone the engine was warm but not warm enough to move the temperature gauge past the 100 degree mark and outside temperature was 86 degrees the pressure was 57psi which according to the gauge is good. i don't know what to test or check. any help greatly appreciated with this warm weather

 

I think in order to get a proper A/C pressure reading the compress needs to be running. Did you try to jumper the low pressure switch connected to the side of the canister? There also a method to "Hot Wire" the compressor clutch.

 

i havnt tried jumping or hot wire anything im not sure how to properly do it to anything on the a/c system and im not sure what the results would mean either