Automatic Temperature Control (ATC) - Dual Zone

The dual zone automatic temperature control (ATC) heating-A/C system allows completely independent side-to-side temperature control of the discharge air.

The dual zone ATC system includes a dust and odor filter. The particulate air filter element is the same size as the A/C evaporator to ensure ample capacity. A door at the base of the HVAC housing below the glove box provides easy access to the particular air filter element.

FRONT A/C-HEATER CONTROL

ATC Dual Zone Front A/C-Heater Control:

The ATC A/C-heater control is located in the instrument panel and contains:
- two temperature set controls for completely independent side-to-side temperature control of the discharged air. The full range of temperature that the system can produce in any mode is available on either side of the vehicle by independently adjusting the controls.
- a power on/off switch. Allows the heating-A/C system to be completely turned Off. The display indicates only the outside temperature when the system is off.
- a display screen to indicate the heating-A/C system operational modes and inside and outside temperatures.
- a dual zone control. Allows the selection of either single (driver) or dual (driver and passenger) temperature control mode.
- a separate front window defogger on/off switch. Contains an LED that illuminates to indicate when the front widow defroster is manually selected.
- a rear window defogger on/off switch. Contains an LED that illuminates to indicate when the EBL system is On.
- an air conditioning on/off switch. Contains an LED that illuminates to indicate when the A/C mode is manually selected.
- an air recirculation on/off switch. Contains an LED that illuminates to indicate when the Recirculation mode is manually selected.
- a manual mode switch. Allows the operator to manually select the air delivery mode.
- two infrared temperature sensors which independently measure the surface temperature of the driver and front seat passenger.
- a manual blower fan speed switch. Allows the operator to manually select six different fan speeds.
- a outside temperature switch. Allows the operator to select either outside air or passenger set temperatures.
- a rear blower fan switch. Allows the operator to set the rear blower fan speed to AUTO for automatic speed adjustment, or to REAR to give control to the intermediate seat occupants, or OFF to shut the rear blower motor down.
- an auto high and an auto low switch. Allows various modes of automatic temperature control operation. Contains LEDs that illuminate to indicate when operational.

The Computer logic remembers the settings of the A/C-heater controls when the ignition is turned to Off and, retains those settings after a restart, etc. The computer logic also provides variable air recirculation under high temperature and humidity conditions. Recirculation mode is initially accompanied by outside air to help remove any humidity within the passenger compartment and will gradually approach full recirculation over a broad range of temperatures.

REAR A/C-HEATER CONTROL
Primary controls for the rear compartment is on the instrument panel. The front A/C-heater control allows the driver to set the rear compartment blower fan speed, turn the rear unit off, or to give control to the intermediate seat occupants by switching to the REAR position. When the rear system is controlled from the instrument panel, rear blower fan speed is automatically controlled based on the front A/C-heater control temperature setting. Air flow through the floor console is directed through upper or lower outlets based on the front mode settings.

The rear rotary blower fan control is centrally mounted on the center floor console between the second row seats and allows control of the rear blower fan speed by intermediate seat passengers.

The dual zone automatic temperature control (ATC) system automatically maintains the interior comfort level desired by the driver and front seat passenger. This is accomplished by using two infrared sensors within the A/C-heater control which is located at the center of the instrument panel. The two infrared sensors independently measure the surface temperature of the driver and front seat passenger. Based on the sensor input, the system automatically adjusts the air temperature, the air- flow volume, the airflow distribution, and amount of inside air recirculation to maintain front seat occupant comfort, even under changing outside weather conditions.

When DUAL is displayed on the A/C-heater control, the driver and passenger air outlet temperatures can be individually adjusted from the two independent TEMP buttons. When a front seat passenger is not present, pressing the DUAL button will:
- disable the passenger side infrared sensor and control the entire system based only on the driver side temperature setting.
- replace the passenger side temperature setting in the display to the outside temperature reading.

Pressing the DUAL button a second time or adjusting the passenger side TEMP button will:
- reactivate the passenger side infrared sensor.
- return the system to dual independent temperature operation.

This ATC system offers several manual override features. The indicator light in both the AUTO HI or AUTO LO buttons will turn off when the system is being used in the manual mode. The fan speed, airflow distribution, and outside air/recirculated air can be manually adjusted.

The front blower fan control can be set to any fixed blower fan speed by pressing the rocker switch up or down. This allows the front occupants to control the volume of air circulated in the vehicle and cancel the auto mode. The fan will now operate at a fixed speed until additional speeds are selected or until either the AUTO HI or AUTO LO buttons are pressed. The system will continue to automatically adjust air temperature and airflow distribution.

When the outside air contains smoke, odors, high humidity, or if rapid cooling is desired, interior air can be recirculated by pressing the recirculation button. The recirculate symbol will illuminate in the display when this button is selected.

The outside temperature can be shown in the A/C-heater control display by pressing the OUTSIDE TEMP button. After pressing this button, the front seat passenger side temperature setting display will be replaced with the current outside temperature. Pressing the OUTSIDE TEMP button again or pressing the passenger side TEMP button will return the display to the passenger side temperature setting.
- The system automatically adjusts the temperature, mode and fan speed.
- When the heating- A/C system is off, the recirculation door is automatically closed to prevent outside air from entering the passenger compartment.
- Air conditioning is available in any mode by pressing the snowflake, A/C on/off, button.

To provide maximum comfort in the automatic mode during cold start-ups, the blower fan will remain off and DELAY will appear in the display until the engine warms up. The estimated the time remaining until the DELAY is complete will appear periodically in the display. However, the fan will engage immediately if the defrost mode is selected or by pushing the blower switch and manually adjusting the fan speed.