Daytime Running Lamps Malfunction
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Daytime Running Lamps Malfunction
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Ambient Light/Sunload Sensor Signal
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B2645 03
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B2645 07
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B2645 07
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-
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Left/Right Daytime Running Lamp (DRL) and Rear Park Lamp Control
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B2585 02, B3867 02
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1
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2
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-
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Ambient Light/Sunload Sensor Ground
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-
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B2645 07
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-
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-
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1. Daytime Running Lamps (DRL) and Park Lamps Inoperative
2. Daytime Running Lamps (DRL) and Park Lamps Always ON
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Circuit/System Description
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The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 1.4-4.5 V depending on outside lighting conditions. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the DRL and rear park lamps ON.
The BCM receives a signal from the ambient light/sunload sensor indicating a low or high ambient outside light level. Under daylight conditions the BCM will enable the daytime running lamps and rear park lamps. The daytime running lamps and rear park lamps share the same BCM control circuit. With the headlamp switch in the AUTO position, the DRL and rear park lamps will be illuminated at all times with the ignition on and engine running.
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for information on diagnostic tools
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Circuit/System Verification
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1.
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Verify that no other DTC is set.
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3.
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Ignition ON, observe the scan tool Ambient Light Sensor parameter. The reading should be between 1.4-4.5 V and change with ambient light changes.
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1.
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Ignition OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor.
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2.
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Test for less than 5 Ω between the ground circuit harness connector terminal 6 and ground.
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3.
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If greater than the specified range, test the low reference circuit for an open/high resistance.
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4.
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Ignition ON, test for 4.8-5.2 V between the signal circuit harness connector terminal 5 and ground.
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5.
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If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
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6.
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If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
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7.
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If all circuits test normal, test or replace the B10B Ambient Light/Sunload Sensor.
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Dynamic Test
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1.
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Ignition ON, observe the scan tool Ambient Light Sensor parameter. The reading should be between 1.4-4.5 V and change with ambient light changes.
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2.
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Test the B10B Ambient Light/Sunload Sensor by varying the ambient light while monitoring the sensors voltage output.
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3.
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Verify that the voltage output is within the range of the specification.
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4.
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If not within the specified range, replace the B10B Ambient Light/Sunload Sensor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
