If the system has lost refrigerant pressure the system protects the compressor by use of a low system pressure switch that does not allow the compressor to operate if there is not sufficient refrigerant pressure. You need to trace the wiring, check fuses and relays. Bridging the low pressure switch or powering up the compressor directly (using a fused jumper wire) should get the compressor to operate if the compressor clutch is OK and the compressor works (isn't seized).
check your relays under the hood,, I have a 94 camaro myself,, you can swap the relay from any of the relays under the hood. If you do that and still wont turn on your compressor,, try to bypass the pressure switch, if it cycles on, stop, and get your self 2 lbs of r-134a and get a can hooked up to the lower pressure side of your AC system,, start your car, put your temp control on MAX a/c then by pass the low pressure switch again, and quickly open the valve and get freon flowing into your system, after one can has been put in system, disconnect that can,, turn off the a/c and your car,, replace the plug to the low pressure switch,, then start up your car and put A/c on MAX your compressor should be on by it self now, but might cycle on and off, if so,, get your second can of freon and get it in your system, then if all is right your compressor should stay on continuisly