Heating and Air Conditioning: Description and Operation

CONDENSER FAN AND RADIATOR FAN CONTROL
- For the operation of each fan, see COOLING SYSTEM. Description and Operation

A/C Compressor Relay ON Conditions:

COMPRESSOR CONTROL
- The fin thermo sensor, which senses the temperature of the air flowing out of the evaporator, are deactivated with temperature 2°C (28° F) or below.
Here, the engine coolant temperature sensor senses the temperature of engine coolant, and it is turned off at 115°C (239° F) or higher temperatures.
- The dual pressure switch turns OFF when the refrigerant pressure becomes excessively high or low, thus protecting the compressor circuit.
- 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.