Chrysler 300/300 Touring/300C, Dodge Magnum. Manual - part 2334

SENSOR-INFRARED

DESCRIPTION

The infrared sensor is used only on models equipped
with the automatic temperature control (ATC) heating
-A/C system. The infrared temperature sensor consists
of a infrared transducer concealed behind a clear lens
(1) located within the instrument panel mounted A/C-
heater control (2).

OPERATION

The infrared sensor detects thermal radiation emitted by the driver and front passenger seat occupants and their
surroundings and converts its data into a linear pulse width modulated (PWM) output signal which is read by the
automatic temperature control (ATC) A/C-heater control. The ATC A/C-heater control uses the infrared sensor data
as one of the inputs necessary to automatically control the interior cabin temperature level. By using thermal radi-
ation (surface temperature) measurement, rather than an air temperature measurement, the ATC heating-A/C sys-
tem is able to adjust itself to the comfort level as perceived by the occupant. This allows the ATC system to
compensate for other ambient conditions affecting comfort levels, such as solar heat gain or evaporative heat loss.

The ATC system logic responds to the infrared sensor message by calculating and adjusting the air flow tempera-
ture and air flow rate needed to properly obtain and maintain the selected comfort level temperature of the occu-
pants. The A/C-heater control continually monitors the infrared sensor circuits, and will store diagnostic trouble
codes (DTCs) for any problem it detects.

The infrared sensor is diagnosed using a scan tool (Refer to 24 - HEATING & AIR CONDITIONING - DIAGNOSIS
AND TESTING - HEATING AND A/C SYSTEMS) and to 24 - HVAC Electrical Diagnostics for more information.

The infrared sensor cannot be adjusted or repaired and, if faulty or damaged, the entire ATC A/C-heater control
must be replaced.

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CONTROLS

SENSOR-SUN

DESCRIPTION

The automatic temperature control (ATC) heating-A/C
system uses a sun sensor assembly (1) to measure
sun light intensity. The sun sensor assembly incorpo-
rates two sun sensors (2) within a molded plastic case
which is mounted to the instrument panel and a clear
lens (3) that protrudes through the defroster grille. The
wire harness receptacle (4) connects the sun sensors
to the vehicle electrical system through a wire lead
and connector of the instrument panel wire harness.

OPERATION

The ATC heating-A/C system uses two sun sensors to balance the system in response to side-to-side variations in
sun light intensity. Passengers in sun and shadow require different functional settings because they experience very
different temperatures. The sun sensor assembly provides data to the A/C heater control to help determine proper
mode and blend-air door positions and blower motor speeds. The sun sensors are not thermistor type sensors, but
rather photo diodes. For this reason the sun sensors responds to sun light intensity rather than temperature. The
sun sensor assembly is also used to sense day and night conditions for automatic headlight control, if equipped.

The sun sensor is diagnosed using a scan tool (Refer to 24 - HEATING & AIR CONDITIONING - DIAGNOSIS AND
TESTING - HEATING AND A/C SYSTEMS) and to 24 - HVAC Electrical Diagnostics for more information.

The sun sensor assembly cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

DIAGNOSIS AND TESTING

SUN SENSOR

WARNING: On vehicles equipped with airbags, disable the airbag system before attempting any steering
wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the
negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before
performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to
take the proper precautions could result in an accidental airbag deployment and possible personal injury or
death.

The sun sensor assembly is located so that the sun rays will hit the sensors in the same way that it will hit the
driver and the passenger. It is important that the area in front of the sun sensor assembly be unobstructed. Check
for the following:

•

Windshield wipers are properly adjusted.

•

Defroster grille or sun sensor is properly installed. The sun sensor lens should protrude above the defroster
grille.

•

Any stickers on the windshield are not directly in front of the sun sensor.

•

Any items laying on top of the instrument panel are not covering the sun sensor.

CONTROLS

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If the vehicle exhibits a lack of passenger comfort in sunny weather such as in the early afternoon, inspect the
position of the sun sensor assembly. The sun sensor lens should protrude above the defroster grille to insure proper
operation. If the sun sensor is not properly positioned, perform the following procedure:

1. Confirm that the defroster grille is properly installed. If not, repair as required.

2. Remove the defroster grille (Refer to 23 - BODY/INSTRUMENT PANEL/DEFROSTER GRILLE - REMOVAL).

3. Verify that the sun sensor is properly installed to the instrument panel (Refer to 24 - HEATING & AIR CONDI-

TIONING/CONTROLS/SENSOR-SUN - INSTALLATION).

4. Install the defroster grille (Refer to 23 - BODY/INSTRUMENT PANEL/DEFROSTER GRILLE - INSTALLATION).

The A/C-heater control continually monitors the sun sensor circuits and will store diagnostic trouble codes (DTCs)
for any problem it detects. The sun sensor can be tested in the vehicle with a scan tool (Refer to 24 - HEATING &
AIR CONDITIONING - DIAGNOSIS AND TESTING - HEATING AND A/C SYSTEMS) and to 24 - HVAC Electrical
Diagnostics for more information.

REMOVAL

1. Disconnect and isolate the negative battery cable.

2. Remove the defroster grille (Refer to 23 - BODY/

INSTRUMENT

PANEL/DEFROSTER

GRILLE

REMOVAL).

3. Using a trim stick or another suitable wide flat-

blade tool (1), gently pry between both sides of the
sun sensor assembly (2) and the instrument panel
(3) to release the snap clip retainers that secure
the sun sensor.

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CONTROLS

4. Disconnect the wire harness connector (1) from the

sun sensor assembly (2).

5. Remove the sun sensor assembly from the instru-

ment panel (3).

INSTALLATION

1. Position the sun sensor assembly (2) near the

instrument panel (3).

2. Connect the wiring harness connector (1) to the

sun sensor assembly (2).

CONTROLS

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