Evaporator Temperature Sensor / Switch: Description and Operation

Heater/Evaporator Assembly:

A Thermostatic switch cycles the A/C compressor clutch to keep the evaporator from freezing. The thermostat switch capillary tube is inserted into the evaporator housing. If evaporator temperature falls below 32°F (0°C) the thermostat switch opens, A/C compressor clutch relay opens to disengage A/C compressor clutch. This regulates the evaporator temperature between 30° to 40°.

- Switch opens: -1.5°C to + 1.5°C (28°F to 35°F).
- Switch closes: +1.5°C to + 4.5°C (35°F to 40°F).
- Switch opening and closing points must occur with at least 2°C (3.6°F) difference.