AC Compressor isn't coming on...
 

I just bought another 99 Trans Am and the AC compressor clutch doesnt engage when turn the AC on. Where should I start trouble shooting it? I would think its low on freon...is there a low pressure switch you can reset in order to recharge it? If not how can you charge it to see? I am a complete newbie when it comes to AC problems so please help me get an idea of where to start.

You can jump the compressor clutch direct to the battery, and that will allow you to recharge the system. But before you do that, you need to find and fix the leak. Two ways to do that; one is with an electronic leak detector and the other is with dye (in the refrigerant).