Air Handling

All of the door actuators contain a reversible electric motor and a potentiometer. The potentiometer circuit consists of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal to the HVAC control module from the contact wiper indicates the position of the actuator door. The HVAC control module powers the actuator motors to move the doors to the desired positions. The desired door positions are calculated by the HVAC control module based on the set temperature, in-vehicle temperature and ambient air temperature.

The HVAC control module controls the blower speed by sending a PWM signal to the blower motor speed control.

All airflow from the blower motor passes through the evaporator core. Based on the climate control system temperature settings, the temperature door actuator directs airflow through the heater core as needed. The defrost/panel/floor mode door actuator controls the airflow to the defrost, footwell or register vents. The air source is from outside air or recirculated passenger compartment air as determined by the air inlet door position.

Max A/C 

When MAX A/C is selected:

• the air inlet door actuator closes off outside air and admits only recirculated air.
• the recirc button is disabled and the indicator is illuminated.
• the defrost/panel/floor door directs airflow to the instrument panel A/C registers.
• blended air temperature is available.
• the A/C request button is illuminated and disabled.
• the A/C compressor operates if the outside temperature is above approximately 0 °C (32 °F).
• the blower motor is on.

PANEL 

When PANEL is selected:

• the recirc request button is enabled. If the recirc request button is selected (indicator on), the air inlet door actuator closes off outside air from entering the passenger compartment. If the recirc request button is not selected (indicator off), the air inlet door actuator admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the instrument panel A/C registers.
• blended air temperature is available.
• the A/C request button is enabled. The A/C compressor operates and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0 °C (32 °F).
• the blower motor is on.

PANEL/FLOOR 

When PANEL/FLOOR is selected:

• the recirc request button is enabled. If the recirc request button is selected (indicator on), the air inlet door actuator closes off outside air from entering the passenger compartment. If the recirc request button is not selected (indicator off), the air inlet door actuator admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the floor duct and the instrument panel A/C registers. A small amount of airflow from the side window demisters and defrost duct is present.
• blended air temperature is available.
• the A/C request button is enabled. The A/C compressor operates and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0 °C (32 °F).
• the blower motor is on.

OFF 

When OFF is selected:

• the recirc request button is disabled.
• the air inlet door actuator closes off outside air and admits only recirculated air.
• the A/C request button is disabled.
• the blower motor is off.

FLOOR 

When FLOOR is selected:

• the recirc request button is enabled. If the recirc request button is selected (indicator on), the air inlet door actuator closes off outside air from entering the passenger compartment. If the recirc request button is not selected (indicator off), the air inlet door actuator admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the floor duct. A small amount of airflow from the defroster duct and side window demisters is present.
• blended air temperature is available.
• the A/C request button is enabled. The A/C compressor operates and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0 °C (32 °F).
• the blower motor is on.

FLOOR/DEFROST 

When the FLOOR/DEFROST is selected:

• the recirc request button is enabled. If the recirc request button is selected (indicator on), the air inlet door actuator closes off outside air from entering the passenger compartment. If the recirc request button is not selected (indicator off), the air inlet door actuator admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the floor duct, the defroster duct and the side window demisters.
• blended air temperature is available.
• the A/C request button and indicator can be toggled. To reduce fogging, the A/C compressor operates automatically, regardless of indicator status, if the outside temperature is above approximately 0 °C (32 °F).
• the blower motor is on.

DEFROST 

When DEFROST is selected:

• the air inlet door actuator opens, admitting only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct is present.
• blended air temperature is available.
• the A/C request button and indicator can be toggled. To reduce fogging, the A/C compressor operates automatically, regardless of indicator status, if the outside temperature is above approximately 0 °C (32 °F).
• the blower motor is on.