Air conditioner trouble

I have a 1997 Chevy Lumina with a 3.1L engine. Recently the AC just stopped working. Now it just blows warm air. Usually when I’m sitting in the car and I turn the AC on I can hear the engine idle a little higher because the compressor kicked on, but that doesn’t happen anymore. It's like the switches in the car don't get the signal to the compressor. I've had someone sit in the car and turn on and off the AC while I watch the compressor to try and see the clutch engage or something, but I’m not sure what it used to look like when it worked, so that didn't help much. It just remained the same whether the switch was on or off. I checked fuses, and relays associated with the AC, but they all seem like they are in working condition. I don't want to go out and pay for a whole new compressor, and I was hoping someone out there might have some more suggestions for possible fixes. Thanks!

Well, you either have an electrical failure, low pressure switch not working, etc, or you had a catastrophic refrigerant leak.

If it were me, I'd buy an R134a kit with a fill hose (about $30-$40), and try shooting a can in it, see if the compressor kicks in. If so, it lost it all. You may be able to find the leak if it's that large.