Auto Air Conditioning & Heater Repair: 1998 Ford F 150 Lariot 5.4 Triton, ford f 150, fx series

Question
My trucks A/C has developed a problem to where it stops working after about 20 mins of running. I turned the truck on and turned the A/C to Max and checked the pressure with a guage and it showed it was fine. I noticed the Compressor was not spinning so I turnned the truck off and spun the compressor plate and it felt free. I don't think it would be an electrical problem because it works at first. Any ideas?  

Answer
Hello owner of 98 Lariot, Sounds like you may have a presuure cycle switch that is shutting off the compressor. Is the a/c cold that first 20 min?. Ford designed it
to shut-off if there is a blockage in the orifice line. Their a/c compressor,called the FX series has given them some problems.They tend to break down internally and debris from the compressor plugs-up the
liquid orifice line. Recommend seeing a a/c shop. Let me know your findings.

Aloha,Davidt