Ron,
Could be several things wrong causing your lack of cold air. I'm not an AC person so I'm not going to try to diagnose the problem. BUT, when my compressor went out on my coach I took it to Elite Coach in Ephrata, PA for repairs. Nelson, service manager, told me about an upgrade that Prevost has to replace the weak system originally on our buses. It is a new system consisting of condenser, compressor, valves, hoses, evaparator, etc, and is almost 50 percent larger than the original. I had the system installed on my bus two years ago and have been very satisfied with it.