As an FYI.......for Corvette's, it was found that the A/C systems were overfilled with refrigerant at the factory. When the internal line pressures reached critical during use in the summer heat (I'm in Phoenix as well), the pressure switch will disengage the compressor.
Have a technician check for an overfilled refrigerant status in the A/C system.
Steve at Loud Pedal in Tempe could probably check this for you
