Broken A/c
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#2
Most likely it has a leak somewhere in the system, you need to have it evacuated and recharged, they will add uv tracer dye to the system and have you come back in a couple weeks so they can see where the dye is leaking out. It could be leaking from the condensor, evaporator, or any of the lines in between. There is a small possiblity that there is an electrical problem that is causing the compressor clutch to not engage, but thats less likely and it will only take a shop a few seconds to check that after they get some refrigerent in the system. If your truck is a 92 it might have an r-12 system and they will want to convert it to an r134a system if it hasn't already been done. Ccnverting it will actually be cheaper than refilling it with r-12 since r-12 is about $80 a pound now, and r134a is less than $10 a pound.
-Jon
-Jon