Compressor HVAC: Description and Operation

Compressor control
When operating the air conditioning switch
- The air thermo sensor, which senses the temperature of the air flowing out of the evaporator, deactivates the compressor at -2°C (28°F) or below.
Here, the engine coolant temperature sensor senses the temperature of engine coolant, and turns off the compressor at 115°C (239°F) or higher temperatures.
- The dual pressure switch turns OFF when the refrigerant pressure becomes excessively high A/C Compressor Relay ON Conditions or low, thus protecting the compressor circuit. (See Table below.)
- When these two sensors are all activated, the dual pressure switch is ON, and the ignition switch, blower switch, and air conditioning switch are ON, the A/C compressor relay is energized.
When operating the air outlet changeover control knob
- When the air outlet changeover control knob is moved to DEF or DEF/FOOT position, the micro switch, which is connected in series to the air conditioning switch, is turned on. The other compressor control than the above is the same as that when operating the air conditioning switch.