If the compressor is not going on then recharge the A/C. If it doesn't work after recharge you may have a severe leak. If you can't see any leakage does your windshield frost up after charging? If it does then you may have a big problem . See a mechanic and get an estimate. Depending on the cars age and value you might wanna get used to rolling the windows down in hot weather.
Low on freon, bad sensor, etc
Low on freon, faulty pressure switch, faulty clutch. Jumper the low pressure switch with a paperclip (can running, AC on), if the clutch cycles, it's either low on freon, or the low pressure switch is bad.
low freon, bad pressure switch, bad compressor clutch.
low on freon
low freon
low freon
Try jumping the two terminals of the wires which go to the low pressure switch. That's a possibility, as is low refrigerant, a bad compressor clutch, or a faulty fuse or relay to the compressor clutch.
If the clutch is engaged & turning, there should be no problem getting freon into the system, unless the orifice tube is plugged.
low freon
Most Likely Low With Freon.
Low freon, bad compressor, bad clutch, bad pressure switch (could be multiple of these), bad switch...the list goes on. Best bet is to take it to a mechanic for a diagnosis.
Any of the following can cause this...... 1. System is low on freon... 2. A/C clutch is bad... 3. Clutch coil is bad.... 4. Wire harness is bad.... 5. Inside controller is bad.... 6. Pressure switch or relay is bad...