Low Charge Protection Switch
WARNING: This page is about a different car, the 2006 Lincoln Navigator and 2006 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
The low charge protection switch is used to prevent A/C compressor damage in the event of a low refrigerant charge, by interrupting the evaporator discharge air temperature sensor signal to the PCM, when the low side refrigerant pressure drops below acceptable levels. The electrical switch contacts open when the suction pressure drops below normal levels. The contacts close when the suction pressure rises. For specifications regarding operating pressure(s), refer to A/C COMPRESSOR -- EXTERNAL LEAK TEST .