A/C not cycling and freezing up.

A/C lines were frosting and the evaporator and vent temperatures were reported to go below freezing. After rectifying a compressor O-ring leak and re-gassing, the system operation appeared inconsistent depending on test conditions and temperature settings. It was later clarified that this VY system does not normally cycle the compressor clutch to control evaporator temperature, as it uses a variable displacement compressor with a mechanical control valve to regulate suction pressure and evaporator temperature.