It can be many things. Check to see it the compressor clutch is plugged in or the connections are corroded or loose. If this is ok, then take it to a professional. Check your relays dun dun dun duuuuuuuuuuuunnnn... these badboys don't kick on if they don't have enough charge its true.. check that....
Find out the reason the compressor isn't engaging, of course! It could be a problem with the clutch, a problem with the low pressure switch, a low refrigerant level (likely caused by a leak in the system which needs to be repaired), or the compressor itself could be defective. Without any sort of diagnosis, we have no way of narrowing down the causes. You won't get cold air without the compressor, so that has to be dealt with.
There could be a problem with the power of common ground to the Cavalier light and sun roof. Check the fuses and wiring for the problem.
Could be a number of reasons. It's pretty much impossible to narrow it down without knowing what the actual symptoms are. When you say your AC doesn't start, you could mean the blower fan isn't kicking on, you could mean your AC compressor isn't kicking on.... the question's much too vague.
You probably need a new air filter for your a/c The clicking is probably caused by the clutch on the compressor. If the Ac isn't charged enough it could cause this to kick the compressor off and on. You compressor could also be bad. You werent real clear what the problem was. Hope this helps.
The problem could be the relay that goes to the compressor this could be faulted out causing the compressor to run constantly. However if this isn't the case then a quick check of the fuse may also resolve the problem.
It means that the compressor is broken inside, and it is time to replace it.
Bring to a shop that has an ABS scanner to determine the problem
Bad solenoid, leaking bags
Could be the connector of your fan blower(vacuum) which is located beneath the glove compartment box. Or may be the blower is bad.
Bad compressor? Air leak in system? Excessive vehicle weight?
If it's blowing and you can tell the compressor is still kicking on when you turn the A/C on, the Coolant probably just needs to be recharged. Especially in a 9 year old car.
The abs light being on for a 2000 Cavalier indicates a brake problem. The brakes could lock up when the pedal is pushes hard, or pulse.