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SENSOR-SUN Jeep Commander I

HVAC Systems - Service Information 3 illustrations ~545 words

SENSOR-SUN

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 on MTC equipped vehicles.

The sun sensor is diagnosed using a scan tool. See DIAGNOSIS AND TESTING or appropriate HVAC ELECTRICAL DIAGNOSTICS article for more information.

The sun sensor assembly cannot be adjusted or repaired and must be replaced if found inoperative or damaged.

WARNINGDisable 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. If the vehicle exhibits a lack of passenger comfort in sunny weather such as in the early afternoon, inspect the area around the sun sensor on top of the dash panel. It is important that the area of the sun sensor be unobstructed from plain view. Check for the following

  1. Windshield wipers are properly adjusted.
  2. Sun sensor is properly installed. See «INSTALLATION»(ref-288218-S04983077382008062000000) .
  3. Any stickers on the windshield are not directly in front of the sun sensor.
  4. Any items laying on top of the instrument panel are not covering the sun sensor.

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. See DIAGNOSIS AND TESTING or appropriate HVAC ELECTRICAL DIAGNOSTICS article for more information.

WARNINGDisable 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.

Scheme 52

Scheme 52
Scheme 52

Scheme 53

Scheme 53
Scheme 53
  1. Disconnect and isolate the negative battery cable.
  2. Using trim stick C-4755 or equivalent (1), gently pry between both sides of the sun sensor (2) and the instrument panel (3) to release the snap clip retainers located at the front of the sensor near the windshield.
  3. Carefully pull the sun sensor (2) partially out of the instrument panel (3) and disconnect the wire harness connector (1) from the sensor.
  4. Remove the sun sensor from the vehicle.
  1. Position the sun sensor (2) near the instrument panel (3).
  2. Connect the wiring harness connector (1) to the sun sensor.
  3. Align the tab on the sun sensor with the opening in the instrument panel and install the sensor onto the instrument panel. Make sure that the sensor's retaining clips located at the front of the sensor near the windshield are fully engaged to the instrument panel.
  4. Reconnect the negative battery cable.

Scheme 54

Scheme 54: TRANSDUCER-A/C PRESSURE
Scheme 54: TRANSDUCER-A/C PRESSURE

The A/C pressure transducer (1) is a switch that is installed on a fitting located on the A/C discharge line. An internally threaded fitting on the A/C pressure transducer connect it to the externally threaded Schrader-type fitting on the A/C discharge line. A rubber O-ring seals the connection between the A/C pressure transducer and the discharge line fitting. The A/C pressure transducer is connected to the vehicle electrical system by a molded plastic connector with three terminals.