Cadillac Repair: 2000 Escalade A/C, compressor operation, sensor readings

Question
Just bought and am having some problems with A/C. Will blow cold air 37 degrees but then intermittently will blow warm air. Then will go back to blowing cold air. Mechanic added freon with dye and showed no obvious leaks. Shows good pressure when blowing cold. Have not been able to check pressure when blowing warm, doesn't do it when at mechanics. Any ideas? Thanks for your help.

Answer
Hi Judy, 37 is pretty cold and maybe you have too much freon in the system and it is causing iceing up that is shutting down the a/c compressor operation. Monitoring the pressures as well as checking for codes and sensor readings with a scan tool might be necessary. You also have to have the problem act up at the shop before it can be diagnosed. If you had it to the dealer maybe a call to the tech hotline might show a pattern of intermittant operations. The a/c compressor relay might be where the problem lies. Bill