One of the symptoms of a non-working A/C system is lack of voltage to the A/C compressor clutch circuit. This test requires use of a multi-meter to determine if you have 12volts DC at the connector for the A/C clutch.
It helps to have your front end up on ramps, or at least sitting on jack stands. This gives you plenty of room to get underneath to disconnect the connector for this test.
For safety reasons, it is best to do these steps in order. Failure to do so could lead to having your hand come in contact with the moving accessory drive belt.
Step 1- Disconnect the electrical connector from the A/C clutch.
Step 2- Turn on your multi-meter, set it for 20V DC and connect to the electrical wire that you just disconnected. NOT the connector on the compressor.
Step 3- Start car and turn your A/C on to MAX.
Step 4- Verify 12-13 volts on your meter.