need a lesson in A/C

You could use a socket to turn the compressor by hand. Then if that seems ok. Crank it up, set controller for cold air, Use a carter pin to jump the wire connector removed from low pressure switch. If clutch engages, and compressor runs, don't run the compressor for a long time until you know the system is not low on Freon. If it is low on Freon, it got out somewhere. Dusty crud build up often tells the tale since some of the oil escapes too. Where you put that socket is a common place. That shaft seal can leak. owner would repeatedly add Freon. Oil loss causes a messy build up just above on the hood insulation.