My air hasn't been blowing cool lately. I'm afraid it's the compressor. I heard a clicking sound from the engine before I stopped using the air completely a week ago, and it's been quiet since then. I want to start troubleshooting it, though. I'm going to get a freon tester today and check that out. What's the best process for troubleshooting an A/C system, from the cheapest fix on up? Is there a way to definitely check if the compressor is good or bad? Thanks.

Other than catastrophic failure where the compressor or it's clutch freeze up, there really is no way to know if the compressor is bad by just looking at it.   You'll need a set of A/C manifold gages to check for internal damage.  typical internal damage involves broken read valves, that manifest themselves as low high-side pressure and high low-side pressure in the A/C system; indicating the compressor just isn't doing it's job.   You might do as I did under that circumstance, and put a $15 junkyard compressor in your van, and do a quick recharge at home using an R134 conversion kit.  Just make sure that you you put the correct volume of R134 Esther oil in the system after draining as much of the original oil as possible.  It isn't necessary to vacuum the system down, though the efficiency will be lowered if you don't.    I originally did my Aerostar van this way 2 years ago, and it lasted two seasons with no problems.  Then a rock took out my condenser in front of the radiator.  I will be replacing it and recharging the same way as soon as I can hit the wrecking yard for another condenser.   Preston III