Climate Control System Operation

Electronic Manual Temperature Control (EMTC) System 

The electronic manual temperature control (EMTC) system operation is determined by the settings on the HVAC module - EMTC. The EMTC system is composed of the HVAC module - EMTC, blower motor resistor, mode door actuator, air inlet door actuator and temperature blend door actuator to control the various functions.

The blower motor switch:

• sets the blower motor speed.
• directs the blower motor path to ground through the blower motor resistor to allow blower motor operation in LO, MED LO and MED HI.
• directs the blower motor path directly to ground, bypassing the blower motor resistor to allow blower motor operation in HI.

The A/C request button:

• can command the A/C compressor ON (when the function selector switch is in PANEL, FLOOR/PANEL, FLOOR/DEFROST and FLOOR) when the A/C request switch is pressed. Indicator illuminates when A/C request switch is toggled ON.
• is inoperative in MAX A/C, OFF and DEFROST.
• indicator illuminates when the function selector switch is in MAX A/C and cannot be toggled.
• indicator does not illuminate in OFF and cannot be toggled.
• indicator does not illuminate in DEFROST but can be toggled ON or OFF. The A/C compressor will operate regardless of indicator status if the outside air temperature is above 6°C (43°F).
• is serviced only with the climate control module.

The function selector knob:

• selects airflow direction.

The air recirculation button:

• selects either recirculated or outside air source.
• recirculates air in any mode except DEFROST, if requested.
• is disabled in MAX A/C or OFF mode where recirculated air only is used.
• is disabled in DEFROST mode where outside air only is used.
• is serviced only with the climate control module.

The temperature selector knob:

• selects full warm and full cool as well as blended outlet temperatures.

The HVAC module - EMTC also includes:

• a rear window DEFROST button. Refer to GLASS, FRAMES & MECHANISMS article.

Dual Automatic Temperature Control (DATC) System 

The dual automatic temperature control (DATC) system operation is determined by the settings on the HVAC module - DATC. The DATC system automatically maintains a selected temperature for vehicle interior comfort. The DATC system is composed of the HVAC module - DATC, blower motor speed control, mode door actuator, air inlet door actuator, temperature blend door actuator, in-vehicle temperature sensor, ambient temperature sensor, evaporator temperature sensor and solar radiation sensor to control the various functions.

The HVAC module - DATC will display outside air temperature when the EXT button is pressed.

When the HVAC module - DATC is set to AUTO:

• the air distribution direction, blower motor speed and A/C compressor operation are automatically controlled based on the temperature(s) selected.

The HVAC module - DATC manual override settings:

• allow the air distribution direction to be manually selected.
• allow the blower motor speed to be manually selected.
• allow RECIRCULATION mode to be manually selected in all modes except DEFROST. The A/C request can be cancelled by pressing the A/C request switch, turning the indicator OFF.
• allow A/C compressor operation to be manually selected except in DEFROST.

The HVAC module - DATC also includes:

• a rear window DEFROST button. Refer to GLASS, FRAMES & MECHANISMS article.
• heated/cooled seat controls. Refer to SEATING article.