HVAC Control Description

HVAC control module calculates the target temperature control door position based on signals from the temperature selector, inside air temperature sensor, outside air temperature sensor and sunload sensor and controls the temperature control actuator so that the current position of the temperature control door matches its target position.

HVAC control module calculates the target blower fan speed based on signals from the temperature selector, inside air temperature sensor, outside air temperature sensor, ECT sensor and sunload sensor, compares the speed thus calculated with the current blower fan speed inputted from the blower motor controller to adjust the current blower fan speed to the target level.

HVAC control module calculates the target temperature control door position based on signals from the temperature selector, inside air temperature sensor, outside air temperature sensor, ECT sensor and sunload sensor. Using thus obtained target temperature control door position, it further calculates the target air flow control door position and controls the air flow control actuator so that the current air flow control door position becomes the target position.

HVAC control module determines the air intake position based on signals from the temperature selector, inside air temperature sensor and outside air temperature sensor and controls the air intake control actuator.

Furthermore, when the defroster switch is turned on, HVAC control module fixes the position of the air intake control door to the FRESH (FRE) position to clear fog from windshield.

HVAC control module outputs A/C switch ON signal to ECM via BCM when the vehicle state satisfies the conditions described below.

ECM and BCM are using CAN communication system to communicate with other control modules. For more detail of CAN communication, refer to “Communication System Description”.

ECM turns ON the A/C compressor relay when the vehicle state satisfies the conditions described below.

ECM turns ON the radiator cooling fan relay at the same time when ECM turns ON the A/C compressor relay.

Refer to “HVAC System Construction” in HVAC System Description:Manual Type.