An air conditioning control system for an automotive vehicle having an internal combustion engine. A variable capacity compressor has a pump having displacement thereof variable in response to a change in pressure within a controlled pressure chamber, a communication passage communicating between a low pressure chamber and the controlled pressure chamber, and a valve disposed to vary an opening area of the communication passage. An electromagnetic clutch connects and disconnects the compressor to and from the engine. An evaporator is connected to the compressor. A control unit controls the capacity of the compressor by supplying the valve with control current normally set within a predetermined range, to vary the opening area of the communication passage such that the temperature of outlet air from the evaporator becomes equal to a desired value. The control unit supplies the control current having a predetermined value larger than the above predetermined range over a predetermined time period to control the capacity of the compressor to the minimum value, when the electromagnetic clutch is brought into an engaged state from a disengaged state.