Electronic Automatic Temperature Control

SYSTEM AIRFLOW DESCRIPTION - ELECTRONIC AUTOMATIC TEMPERATURE CONTROL

AUTO
When AUTO is selected:
- The temperature control setting is manually set to the desired settings.
- The air inlet door vacuum control motor is automatically controlled by the RCC module, based on the temperature setting.
- The mode door vacuum control motors are automatically controlled by the RCC module based on the temperature setting.
- The A/C compressor is automatically controlled by the RCC module based on the temperature setting. The A/C compressor will not operate if the outside temperature is lower than approximately 6°C (43°F).
- The blower motor is on. The blower motor speed is automatically controlled by the RCC module based on the temperature setting, but can be manually overridden.

OFF
When OFF is selected:
- The air inlet door vacuum control motor is at full vacuum, closing off outside air from entering the passenger compartment.
- The defrost door vacuum control motors are at no vacuum, and the panel/floor door vacuum control motor is at full vacuum, closing off airflow to the defrost duct, side window demisters, floor duct, instrument panel A/C registers.
- The A/C compressor will not operate.
- The blower motor is OFF.

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 door vacuum control motors are at full vacuum and the panel/floor door vacuum control motor is at no vacuum, directing airflow to the instrument panel A/C registers.
- Blended air temperature is available. Only when A/C compressor operation has been selected by pressing the A/C request button (indicator on), can the airflow temperature be cooled below the outside air temperature.
- The A/C request button is enabled. The A/C compressor will operate and the indicator will illuminate if the A/C request button is selected and the outside temperature is above approximately 6°C (43°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 door vacuum control motors are at full vacuum and the panel/floor door vacuum control motor is at partial vacuum, directing airflow to the instrument panel A/C registers and the floor duct.
- Blended air temperature is available. Only when A/C compressor operation has been selected by pressing the A/C request button (indicator on), can the airflow temperature be cooled below the outside air temperature.
- The A/C request button is enabled. The A/C compressor will operate and the indicator will illuminate if the A/C request button is selected and the outside temperature is above approximately 6°C (43°F).
- The blower motor is on.

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 panel/floor door vacuum control motor is at full vacuum and the defrost door vacuum control motors are at no vacuum, directing airflow to the floor duct.
- Blended air temperature is available. Only when A/C compressor operation has been selected by pressing the A/C request button (indicator on), can the airflow temperature be cooled below the outside air temperature.
- The A/C request button is enabled. The A/C compressor will operate and the indicator will illuminate if the A/C request button is selected and the outside temperature is above approximately 6°C (43°F).
- The blower motor is on.

FLOOR/DEFROST
When 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 panel/floor door vacuum control motor is at partial vacuum and the defrost door vacuum control motors are at no vacuum, directing airflow to the floor duct, the defroster duct and the side window demisters.
- The temperature can be adjusted to heat or cool the air below the outside temperature.
- The A/C request button will always toggle the indicator and will only operate the A/C compressor when the recirc button is in fresh air mode and the outside temperature is above approximately 6°C (43°F).
- The blower motor is on.

DEFROST
When DEFROST is selected:
- The recirc request button and indicator is enabled. Regardless of button and indicator status, the air inlet door actuator admits only outside air into the passenger compartment.
- The panel/floor door, defrost door vacuum control motors are at no vacuum, directing airflow to the defrost duct and the side window demisters.
- The temperature can be adjusted to heat or cool the air below the outside temperature.
- The A/C request button will illuminate and is enabled. To reduce fogging, the A/C compressor will operate automatically, regardless of indicator status, if the outside temperature is above approximately 6°C (43°F).
- The blower motor is on.

Electronic Automatic Temperature Control System Electrical Components, Part 1:

Electronic Automatic Temperature Control System Electrical Components, Part 2:

Electronic Automatic Temperature Control Components