Likely low in Freon. Verify if compressor clutch is engaged and compressor is turning. If compressor is turning but air is not cold, shoot a can of R-134 in it, as it is just low. If compressor clutch is not engaged, likely Freon is so low that low pressure cut off switch is open. Shooting a can of R-134 in it wil raise pressure enough to close switch and engage clutch. If still no joy, put gauge set on to verify if pressure is low before shooting second can of Freon in it. If pressure is good, and compressor can be turned by hand, check for power and ground at compressor clutch. If no power at clutch check for power at low and high pressure switches. If no power at switches, check a/c relays and a/c fuses. You can pull fuse box cover off for fuse and relay id.