AC Problems

I have a 2001 Jimmy that the AC has quit. I dont know much about AC, but, I do know that the clutch is not engageing. How do I test to see if the compressor or the clutch is bad? Or seems like maybe there should be a switch somewhere to tell the clutch to engage????? Also, I did try to recharge the system with one of those store bought cans of 134a but it would not take any. I guess the clutch has to be engaged in order for the system to suck it out of the can.

If you look on the left hand side of the firewall in the corner there will be a black box it is for servicing the air..On this box there should be a yellow sticker that tells how much freon you need.Yes the air has to be on max in order for the recharge to take.Also if you are too low on freon the compressor will not cycle.(I found that out with mine.)After you add a can it should start cycling.

Found that there was a loose connection at the low pressure switch. Wasn't "clicked" into position. Thanks for your suggestion.