Buick Regal: Automatic Light Malfunction
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
Diagnostic Fault Information
1. Daytime Running Light Malfunction
Circuit/System Description
The ambient light/sunload sensor is used to monitor outside lighting
conditions. The ambient
light/sunload 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/sunload
sensor signal
circuit to determine if outside lighting conditions are correct for either
daytime running lights or
automatic lamp control when the headlamp switch is in the AUTO position. In
daylight conditions the
BCM will command the daytime running lights ON. During low light conditions the
BCM will
command the low beam headlamps ON.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
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.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B10B Ambient Light/Sunload
Sensor.
2. Test for less than 5 Ω between ground circuit harness connector terminal 6
and ground.
- If greater than the specified range, test the low reference circuit for
an open/high resistance.
3. Ignition ON, test for 4.8 - 5.2 V between B10B Ambient Light/Sunload
Sensor signal circuit
harness connector terminal 5 and ground.
- 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.
- If less than the specified range, test the signal circuit for a short to
ground or an open/high
resistance. If the circuit tests normal, replace the K9 Body Control Module.
4. If all circuits test normal, replace the B10B Ambient Light/Sunload
Sensor.
Component Testing
Static Test
1. 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.
2. Test the B10B Ambient Light/Sunload Sensor by varying the ambient light while
monitoring the
sensors voltage output.
3. Verify that the voltage output is within the range of the specification.
- If not within the specified range, replace the B10B Ambient Light/Sunload
Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic
procedure.
- Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor
Replacement
- Control Module References for BCM replacement, setup and programming
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
1. Cornering Lamps Malfunction
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure:Diagnostic System
Check - Vehicle
Review the description of Strategy Based Diagnosis:Strategy Based
Diagnosis
An overview of each diagnostic category can be found here:Diagnostic
Procedure
1. Raise and support the vehicle.
2. Clean the area around the rear axle fill plug.
3. Place a drain pan under the vehicle.
4.
Differential Clutch Cover Plug(1) - Remove.
5. Rear Axle Housing Filler Plug Gasket(2) - Remove.
6. Check the fluid level. If necessary, fill the differential to the