Bypass the cycling switch and tap the face of the clutch. It's free and takes 30 seconds.
If the clutch engages, the clutch gap needs to be adjusted.
If not, you'll have to dig a bit deeper.
DON'T try to add refrigerant unless you know it actually needs it! Why is it that the first thing people do when their AC doesn't work is grab a can of refrigerant? That's like adding fluid to a slipping trans without even checking the dipstick first.