Compressor Switch "ON"

When the engine speed sensor detects the engine speed at or below the specified value, the solenoid valve is opened so as to transfer the intake manifold vacuum to the throttle opener. The throttle valve is slightly opened by the throttle opener and opener lever which is freely movable on the throttle valve shaft. The engine will then run at a speed resulting from setting off the new throttle valve opening against the compressor's load.