A/C Thermostatic Switch

WARNING: This page is about a different car, the 2004 Lincoln Aviator. However, it is still accessible from the selected car via links, so may be relevant.

The A/C thermostatic switch monitors the temperature of the refrigerant exiting the evaporator core into the TXV. It is used (by the PCM) to prevent freezing of the evaporator core by controlling A/C compressor clutch engagement/disengagement. Battery voltage is sent to the A/C thermostatic switch when the ignition switch is in the RUN position. The A/C thermostatic switch either supplies signal voltage to the PCM, or interrupts the signal voltage. A signal circuit connects the A/C thermostatic switch and the PCM and allows the PCM to monitor whether or not the signal voltage circuit is being completed by the A/C thermostatic switch. The PCM engages the A/C compressor clutch when the signal voltage is present and an A/C request has been received from the climate control assembly.

The A/C thermostatic switch is mounted on the TXV. Thermal grease must be applied to the A/C thermostatic switch probe when installing it into the TXV.