I assume you have no manifold guage set to see the refrigerant pressure. Here's where I'd start, because sometimes it is as easy as the low pressure switch gone bad since you say the compressor doesnt turn on.
On your dryer (the round silver cylinder where AC lines go in and out of) there should be two green wires attached to the pressure switch. Remove the black boot and take a stripped jumper wire and with your ac on inside and engine idling, touch the two terminals of the switch together bypassing the pressure check. Don't run it for more than two seconds though. That's long enough to check your compressor to see if it kicks on. If it kicks on, your pressure is low, or your switch is bad.
Go to harbor freight or northern hydraulics or some place and get a set of manifold guages...it is well worth it.
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