If its not cold either the AC compressor motor is stuffed or your out of gas ie. a leak in your system.
Do a pressure check of your lines.
*EDIT I have many good working parts since i brought all new ones.
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There are many different things that have to work together for ur a/c to work.
A/c compressor, condensor,evaporator,tx valve(thermal expansion), pressure switch, thermistor, and revolution sensor in the compressor.
If any if these are broken ur a/c will stop.
First to check is gas.
U will need pressure gauges to check(or if u have a older style receiver drier it should have a sight glass. U should be able to see green liquid with bubble in the sight glass.)
If u have gas, next to check is power to the compressor. If u have no power to the compressor, it could be the thermistor, pressure switch, actual a/c switch in the climate control(including accossiated wiring/fuses/relay).
Next is to check the tx valve.
If the red light comes on the screen, it means the compressor is told to switch on, but the revolution sensor says its stopped. If that has happened I would suspect the magnetic coil for the compressor clutch is gone but if the did a proper rebuild they would have replaced it.
Another quick thought is check u have a belt on there. It also runs the alternator so if the belts gone u will have bigger problems( so I think that's ok).
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