Climate Control System - Vehicles With: Dual Automatic Temperature Control (DATC) - System Operation

The blower motor pulls air from the air inlet and forces it into the heater core and evaporator core housing and the plenum chamber where it is mixed and distributed.

Blower Motor Speed Control

The blower motor speed control uses a PWM signal from the FCIM to determine the desired blower speed and varies the ground feed for the blower motor to control the speed.

Compressor Clutch Assembly

When battery voltage is applied to the A/C compressor clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley. The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate with the engine. When battery voltage is removed from the A/C compressor clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.

An A/C clutch diode is integrated into the coil for A/C clutch field coil circuit spike suppression.

Evaporator Core

The evaporator core is an aluminum plate/fin type and is located in the climate control housing. A mixture of liquid refrigerant and oil enters the evaporator through the evaporator inlet tube and continues out of the evaporator through the evaporator outlet tube as a vapor. During A/C compressor operation, airflow from the blower motor is cooled and dehumidified as it flows through the evaporator fins.

Heater Core

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core.

Climate Control Housing

The climate control housing directs airflow from the blower motor through the evaporator core and heater core. All airflow from the blower motor passes through the evaporator core. The airflow is directed through or around the heater core by the temperature doors. Airflow is then distributed to the selected outlet by the airflow mode doors.

Air Distribution Door Actuator

The air distribution door actuator contains a reversible electric motor and a potentiometer. The potentiometer allows the FCIM to monitor the position of the airflow mode door.

Air Inlet Door Actuator

The air inlet door actuator contains a reversible electric motor and a potentiometer. The potentiometer allows the FCIM to monitor the position of the air inlet door. The FCIM may adjust the air inlet door depending on the humidity measured by the in-vehicle temperature and humidity sensor. If the vehicle cabin becomes too humid, and recirculated air is not selected, the FCIM adjusts the air inlet door to allow more fresh air. When the humidity level drops, it may adjust back to partial recirculated air. Additionally, when recirculated air is not selected, the FCIM may also adjust the system based on the in-vehicle and outside ambient temperatures to reduce loading on the compressor when required.

Driver Side Temperature Door Actuator

The driver side temperature door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the FCIM to monitor the position of the temperature blend door.

Passenger Side Temperature Door Actuator

The passenger side temperature door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the FCIM to monitor the position of the temperature blend door.

Air Conditioning (A/C) Pressure Transducer

The PCM monitors the discharge pressure measured by the A/C pressure transducer. As the refrigerant