Volvo Repair: a/c problem on 940 volvo wagon, volvo wagon, volvo 940

Question
The A/C on my 94 volvo 940 just went out after we got back home in Florida from our trip to Ohio.It is only blowing hot air now. The compressor is only running occaisionally. I tested the pressure with a guage that came with a can of r134a and even when the compressor was turning, it was still in the yellow zone, green being the lower pressure, optimal place to be. When the compressor was not turning, the pressure was way up in the red (over a hundred pounds of pressure). The pressure was a lot lower on my old 300d mercedes converted to 134a that works fine. Do you have any idea if this is a bad compressor??? or some low pressure/high pressure switch or relay? I hope its not the compressor. Could it also be temperature related? it worked great on the highway all the way from Ohio but will not work properly. Thanks,
Joe

Answer
Joe, where are you in Florida?  It may be a compressor issue but its hard to say without running a few tests. If it is the compressor and its original then it has performed for many years.  Typical compressor life living in Florida is about 5-6 years. Roger