Dual Automatic Temperature Control System

AUTO
When AUTO is selected:
- The temperature control setting(s) is/are manually set to the desired setting(s).
- The recirculation door vacuum control motor is automatically controlled by the DATC module, based on the temperature settings.
- The mode door vacuum control motors are automatically controlled by the DATC module based on the temperature settings.
- The heater control valve is automatically controlled by the DATC module based on the temperature settings.
- The A/C compressor is automatically controlled by the DATC module based on the temperature settings. The A/C compressor will operate if the outside temperature is above than approximately 6°C (43°F).
- The A/C request switch or the RECIRC button, if pressed, will transfer the system to manual operation.
- The blower motor is on. The blower motor speed is automatically controlled by the DATC module based on the temperature settings, but can be manually overridden.

OFF
When OFF is selected:
- The recirculation door vacuum control motor is at full vacuum, closing off outside air to the passenger compartment.
- The defrost door vacuum control motor is at full vacuum and the floor door and panel door vacuum control motors are at no vacuum, closing off airflow to the passenger compartment outlets.
- The heater control valve is at full vacuum, preventing the flow of hot coolant to the heater core.
- The blower motor is OFF.

PANEL
When PANEL is selected:
- The RECIRC button is enabled. If the RECIRC button is pressed (indicator on) the recirculation door vacuum control motor is at full vacuum, closing off outside air to the passenger compartment. If the RECIRC button is not selected (indicator off) the recirculation door vacuum control motor will be at no vacuum, admitting only outside air into the passenger compartment.
- The defrost door and panel door vacuum control motors are at full vacuum and the floor door vacuum control motor is at no vacuum, directing airflow to the instrument panel A/C registers. A small amount of airflow from the floor duct, defroster duct and side window demisters will be present.
- The heater control valve is automatically controlled by the DATC module based on the temperature settings.
- Temperature control can be adjusted by directing the airflow through and around the heater core. Only when A/C compressor operation has been selected by pressing the A/C request switch (indicator on) can the airflow temperature be cooled below that of the ambient (outside) air temperature.
- The A/C request switch is enabled. When the A/C request switch is pressed (indicator on) the A/C compressor will operate if the outside air temperature is above approximately 6°C (43°F).
- The blower motor is on.

PANEL/FLOOR
When PANEL/FLOOR is selected:
- The RECIRC button is enabled. If the RECIRC button is pressed (indicator on) the recirculation door vacuum control motor is at full vacuum, closing off outside air to the passenger compartment. If the RECIRC button is not selected (indicator off) the recirculation door vacuum control motor will be at no vacuum, admitting only outside air into the passenger compartment.
- The defrost door, panel door and floor door vacuum control motors are at full vacuum, directing airflow to the instrument panel A/C registers and to the floor duct. A small amount of airflow from the defroster duct and side window demisters will be present.
- The heater control valve is automatically controlled by the DATC module based on the temperature settings.
- Temperature control can be adjusted by directing the airflow through and around the heater core. Only when A/C compressor operation has been selected by pressing the A/C request switch (indicator on) can the airflow temperature be cooled below that of the ambient (outside) air temperature.
- The A/C request switch is enabled. When the A/C request switch is pressed (indicator on) the A/C compressor will operate if the outside air temperature is above approximately 6°C (43°F).
- The blower motor is on.

FLOOR
When FLOOR is selected:
- The RECIRC button is enabled. If the RECIRC button is pressed (indicator on) the recirculation door vacuum control motor is at full vacuum, closing off outside air to the passenger compartment. A RECIRC door time-out strategy will be used to prevent fogging and the RECIRC function will automatically be turned off after approximately four minutes. If the RECIRC button is not selected (indicator off) the recirculation door vacuum control motor will be at no vacuum, admitting only outside air into the passenger compartment.
- The defrost door and floor door vacuum control motors are at full vacuum and the panel door vacuum control motor is at no vacuum, directing airflow to the floor duct. A small amount of airflow from the instrument panel A/C registers, defroster duet and side window demisters will be present.
- The heater control valve is automatically controlled by the DATC module based on the temperature settings.
- Temperature control can be adjusted by directing the airflow through and around the heater core. Only when A/C compressor operation has been selected by pressing the A/C request switch (indicator on) can the airflow temperature be cooled below that of the ambient (outside) air temperature.
- The A/C request switch is enabled. When the A/C request switch is pressed (indicator on) the A/C compressor will operate if the outside air temperature is above approximately 6°C (43°F).
- The blower motor is on.

FLOOR/DEFROST
When FLOOR/DEFROST is selected:
- The RECIRC button is disabled. The recirculation door vacuum control motor is at no vacuum, admitting only outside air into the passenger compartment.
- The floor door vacuum control motor is at full vacuum and the defrost door and panel door vacuum control motors are at no vacuum, directing airflow to the floor duct, defroster duct and side window demisters. A small amount of airflow from the instrument panel A/C registers will be present.
- The heater control valve is automatically controlled by the DATC module based on the temperature settings.
- Temperature control can be adjusted by directing the airflow through and around the heater core.
- The A/C request switch will be disabled and will not illuminate. The A/C compressor will operate automatically if the outside air temperature is above approximately 6°C (43°F).
- The blower motor is on.

DEFROST
When DEFROST is selected:
- The RECIRC button is disabled. The recirculation door vacuum control motor is at no vacuum, admitting only outside air into the passenger compartment.
- The floor door, defrost door and panel door vacuum control motors are at no vacuum, directing airflow to the defroster duct and side window demisters. A small amount of airflow from the instrument panel A/C registers and the floor duct will be present.
- The heater control valve is automatically controlled by the DATC module based on the temperature settings.
- Temperature control can be adjusted by directing the airflow through and around the heater core.
- The A/C request switch will be disabled and will not illuminate. The A/C compressor will operate automatically if the outside air temperature is above approximately 6°C (43°F).
- The blower motor is on.

Dual Automatic Temperature Control Electrical Components, Part 1:

Dual Automatic Temperature Control Electrical Components, Part 2:

Dual Automatic Temperature Control