Ok the problem, i start the engine and cold air is not coming out, just warm air, so when i start moving the cool air starts to come out.
the next day I did the same thing, but this time i was in a parking lot, engine shut down windows down, but there were some moskitos around,
so i started the engine and the AC, just warm air, then i notice it was overheting, the temperature gauge was about 3/4 from full.
i turned the engine off and let it rest for about an hour, then before i star the engine i refill the coolant tank and it was runing fine, but AC off.
the AC compressor is workin, i can hear the click when turned on, and i got cold air only at night when temperatures are down.

HELP!!!!

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02 Renegade(Cactus Green)/3.7L/45RFE/Mopar Skids/OME HD Springs/Rancho Shocks/16x7 Cragar Soft 8's/245-70-16 AT's/Hella 500/

Does your cabin fan work?

2002 Liberty might have leaked out all of the refrigerant by now. Take it in and have them pressure check / leak test the system.

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02 Liberty Limited
Silver Outside & Taupe Inside
Heated Seats, Sunroof & Infinity speakers
USA Spec I-Pod adaptor, Mopar Sub, Garmin GPS
Tow Package, Select-Trac
Rock Rails, Tow Hooks

That right there is your problem,you have a coolant leak and/or your cooling fan is not working.