Buick Regal: Daytime Running Lamps 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 Lamps Malfunction
Circuit/System Description
The ambient light sensor is used to monitor outside lighting conditions. The
ambient light sensor
provides a voltage signal that will vary between 0.2 and 4.9 V depending on
outside lighting conditions.
The body control module (BCM) provides a 5 V reference signal to the ambient
light sensor and the
HVAC control module provides a low reference ground. The BCM monitors the
ambient light sensor
signal circuit to determine if outside lighting conditions are correct for
either daytime running lamps or
automatic lamp control when the headlamp switch is in the AUTO position. In
daylight conditions the
BCM will command the daytime running lamps ON. During low light conditions the
BCM will
command the low beam headlamps ON. Any function or condition that turns on the
headlamps will
cancel daytime running lamps operation. With the vehicle in park, the BCM
commands the park lamps on which utilizes the same lamps as the daytime running
lamps. Once the vehicle is in gear, the BCM
then commands the daytime running lamps on with a separate circuit from the park
lamps.
Reference Information
Schematic Reference
- Headlights/Daytime Running Lights (DRL) Wiring Schematics
- Body Control System 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
1. Ignition ON.
2. Verify the left daytime running lamp turns ON & OFF when commanding the Left
Dedicated
Daytime Running Lamp ON and OFF with a scan tool.
- If the left daytime running lamp does not turn ON and OFF
Refer to Circuit/System Testing - Daytime Running Lamps Malfunction.
- Go to next step: If the left daytime running lamp turns ON and OFF
3. Verify the right daytime running lamp turns ON & OFF when commanding the
Right Dedicated
Daytime Running Lamp ON and OFF with a scan tool.
- If the right daytime running lamp does not turn ON and OFF
Refer to Circuit/System Testing - Daytime Running Lamps Malfunction.
- Go to next step: If the right daytime running lamp turns ON and OFF
4. Refer to Circuit/System Testing - Ambient Light Sensor Malfunction.
Circuit/System Testing
Daytime Running Lamps Malfunction
1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the
appropriate E13
Headlamp Assembly. It may take up to 2 min for all vehicle systems to power
down.
2. Test for less than 5 Ω between the appropriate ground circuit terminal listed
below and ground.
- Terminal 1 (with T4A)
- Terminal 2 (with T4L)
- If 5 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 5 Ω
3. Connect a test lamp between the control circuit terminal 9 and ground,
ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the appropriate
Dedicated Daytime
Running Lamp ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the appropriate harness connector listed below
at the K9 Body
Control Module.
- X5 - left daytime running lamp
- X7 - right daytime running lamp
- Test for infinite resistance between the control circuit terminal 9 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the appropriate harness connector listed below
at the K9 Body
Control Module, ignition ON.
- X5 - left daytime running lamp
- X7 - right daytime running lamp
- Test for less than 1 V between the control circuit terminal 9 and
ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K9 Body Control Module.
- Go to next step: If the test lamp turns ON and OFF
- Test or replace the daytime running lamp.
Ambient Light Sensor Malfunction
1. Ignition OFF, scan tool disconnected, all doors closed, all accessories
OFF, open and close drivers
door, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor.
It may take up
to 2 min for all vehicle systems to power down.
2. Test for less than 15 Ω between the low reference circuit terminal 6 and
ground.
- Ignition OFF, disconnect the X2 harness connector at the K33 HVAC
Control Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.
- Go to next step: If less than 15 Ω
3. Ignition ON.
4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V.
- Ignition OFF, disconnect the X2 harness connector at the K9 Body Control
Module.
- Test for infinite resistance between the signal circuit terminal 3 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the K9 Body Control Module.
- Go to next step: If greater than 4.65 V
5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and
the low reference circuit
terminal 6.
6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V.
- Ignition OFF, disconnect the X2 harness connector at the K9 Body Control
Module, ignition
ON.
- Test for less than 1 V between the signal circuit terminal 3 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- Go to next step: If less than 0.196 V
7. Test or replace the B10B Ambient Light/Sunload Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor
Replacement
- Headlamp LED Driver Module Replacement
- Control Module References for BCM or HVAC Control Module replacement,
programming, and
setup
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
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
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic
procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic
SEE MORE:
Special Tools
BO-38185 Hose Clamp Pliers
For equivalent regional tools, refer to Special Tools.
Removal Procedure
1. Drain the cooling system.
2. Warm Up Three-Way Catalytic Converter Replacement (2.0L LTG) - Remove.
3.
Turbocharger Coolant Feed Pipe Hollow Screw (1) - Remove.
4. Remove and DISC
NOTE: The following steps must be completed before using the symptom
tables.
1. Before using the symptom diagnostic table, perform the Diagnostic System
Check - Vehicle in
order to verify the following conditions:
There are no DTCs set.
The module can communicate via the serial data.
2. Review