When did the Aerostars switch from the old freon to the new? I just bought a 93 and the A/C needs a charge. My 92 needed a conversion. Anybody know?

 

92 was the last year for most Fords, but it is possible that some of the '93 were still R-12. Easiest way to tell is to look at the fill valves. The R-12 ones are smaller than the R-134 type.

However, since you just bought it, don't just assume it needs a charge, charging a system with a leak can often cause more damage. Have pro test and diagnose it, then decide whether to let them repair, or you do the repairs. A simple diagnosis is cheap, but charging a system that has gotten air can destroy the entire AC system. Worst case scenario with a pro, no serious leaks, it will take a charge, and you get to know that it should continue to work correctly. Or it has serious issues and you decide not to fix it, or decide to fix it yourself, but you also get to know that it has been checked properly.

The exception would be if you are already familiar with AC service and have the proper tools to check, diagnose, evac and recharge the system. If you are not an expert on AC systems, they really are complex enough that the pros should handle that. I'm even a trained AC technician, but since I don't work in that fiel currently and I don't have all the needed equipment, I take mine to a pro for service. Its inexpensive for basic diagnostics at most shops. It only gets expensive when major parts fail, which is costly to do yourself too.