Abstract: A process for operating a motor vehicle air conditioner, which contains a refrigerant circulating system with a compressor and an evaporator. The compressor is deactivated to protect against an insufficient amount of refrigerant being supplied to the compressor when the refrigerant pressure on the high-pressure side of the refrigerant circulating system falls below a definable value. The deactivation to protect against inadequate refrigerant levels is suppressed as long as the temperature of the motor vehicle engine coolant (which is utilized to heat an air flow blown by the air conditioner into the vehicle interior), is below a definable coolant temperature deactivation threshold value and the evaporator temperature is above a definable first evaporator temperature deactivation threshold value. The process can also be used to reduce the tendency of the vehicle's windows to fog up.