Automatic Dual Zone

AUTOMATIC DUAL ZONE





The A/C-heater control (1) for the automatic temperature control (ATC) dual zone heating-A/C system allows both the driver and the front seat passenger the ability to individually regulate air temperature for their side of the vehicle. All controls are identified by ISO graphic symbols.

The dual zone A/C-heater control and integral computer is located in the instrument panel and contains:

- a rotary control for manual and automatic fan speed selection and turning the heating-A/C system off (2).
- push button controls for driver and front seat passenger temperature control of the discharged air (3 and 5).
- a vacuum-fluorescent (VF) digital display (4).
- a rotary control for manual and automatic mode control of the discharged air (6).
- a push button rear window defogger/heated mirror on/off control (7). The push button contains an LED that illuminates when the rear window defogger/heated mirror system is in operation.
- a push button A/C on/off control (8). A Snowflake icon appears in the VF display when the A/C system is in operation.
- a push button synchronize control (9) that synchronizes the temperature of the driver and passenger comfort zones. SYNC appears in the VF display when the system is synchronized, whether under manual or automatic mode.
- a push button air recirculation control (10). The push button contains an LED that illuminates when the recirculation function is manually activated.

The A/C-heater control utilizes integrated circuitry and information carried on the controller area network (CAN) bus to monitor many sensors and switch inputs throughout the vehicle. In response to those inputs, the internal circuitry and programming of the A/C-heater control allows it to control the electronic functions and features of the ATC heating-A/C system.

Some of the inputs received by the A/C-heater control of the ATC heating-A/C system on the CAN bus are as follows:

- Dimming
- Refrigerant Pressure
- A/C Clutch Engage
- Vehicle Identification Number
- Vehicle Odometer
- Engine Coolant Temperature
- Ambient Air Temperature
- System Voltage
- Vehicle Speed
- Engine Speed

Some of the messages broadcasted by the A/C-heater control of the ATC heating-A/C system on the CAN bus are as follows:

- A/C Request
- A/C Select
- EBL Status
- Auto Headlamp Signal

The A/C-heater control for the ATC system is diagnosed using a scan tool Testing and Inspection.

The A/C-heater control cannot be adjusted or repaired and must be replaced if inoperative or damaged.