300 SRT-8 V8-6.1L (2008)
Control Assembly: Description and Operation
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 ATC A/C-heater control and integral computer is located in the instrument panel and contains:
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a push button A/C on/off control (2). The Snowflake button contains an LED that illuminates when the A/C system is in operation.
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a push button rear window defogger on/off control (3). The defogger button contains an amber indicator lamp that illuminates when the rear
window defogger system is in operation.
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an infrared sensor (4) that detects thermal radiation emitted by the front seat occupants and their surroundings
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a push button air recirculation control (5). The Recirculation button contains an amber indicator lamp that illuminates when the recirculation
function is manually activated.
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a rotary control knob for mode control of the discharged air (6).
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two rotary control knobs for individual driver and front seat passenger temperature control of the discharged air (7).
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a rotary control knob for manual and automatic fan speed selection and turning the heating-A/C system off (8).
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Auto mode provides variable air recirculation under high temperature and humidity conditions. Because recirculation is generally accompanied by
increased fan noise, the proportion of recirculated to outside air gradually approaches full recirculation over a broad temperature range.
The A/C-heater control for the ATC dual zone heating-A/C system is diagnosed using a scan tool. Prior to replacing an A/C-heater control, run the
calibration procedure to verify that the concern is not a system issue.
NOTE: ATC A/C-heater controls are NOT interchangeable between other model years or other vehicle lines. If replacement of the A/C-heater
control is required, only use the control designed for the vehicle being serviced.
The A/C-heater control cannot be repaired and must be replaced if found inoperative or damaged.
The A/C-heater control utilizes integrated circuitry and information carried on the controller area network (CAN) B 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
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 B bus are as follows:
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Dimming
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Refrigerant Pressure
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A/C Clutch Engage
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Vehicle Identification Number
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Vehicle Odometer
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Engine Coolant Temperature
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Ambient Air Temperature
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System Voltage
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Vehicle Speed
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Engine Speed
Some of the messages broadcasted by the A/C-heater control of the ATC heating-A/C system on the CAN B bus are as follows:
