Buick Regal: DTC B2625
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.
DTC Descriptor
DTC B2625 02
Display Dimming Pulse Width Modulation Output Circuit Short to Ground
Diagnostic Fault Information
1. Interior Backlighting Malfunction
2. Door Lock Indicator Malfunction
Circuit/System Description
The instrument panel dimmer switch is used to increase and decrease the
brightness of the interior
backlighting components. The instrument panel dimmer switch provides a voltage
signal to the body
control module (BCM) that will increase as the brightness of the lights are
increased and decrease as the
brightness of the lights are decreased. The BCM provides a low reference,
signal, and B+ voltage reference to the instrument panel dimmer switch. When the
instrument panel dimmer switch is placed in
the desired position, the dimmed voltage setting is applied from the instrument
panel dimmer switch
through the instrument panel dimmer switch signal circuit to the BCM. The BCM
interprets the signal
and applies a pulse width modulated voltage through the LED dimming 1 and
dimming 2 control circuits
illuminating the interior backlighting to the requested level of brightness.
Conditions for Running the DTC
- Battery voltage must be between 9 - 16 V.
- Park lamps ON.
Conditions for Setting the DTC
The BCM detects a short to ground in the LED backlight dimming control
circuit terminal 5 X1.
Actions Taken When the DTC Sets
The LED backlight dimming control circuit driver is shut down.
Conditions for Clearing the DTC
- The condition responsible for setting the DTC no longer exists.
- A history DTC will clear once 100 consecutive malfunction - free
ignition cycles have occurred.
Reference Information
Schematic Reference
Interior Lights Dimming Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
Interior 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 Testing
1. Ignition OFF, disconnect the harness connector at the appropriate
component listed below, ignition
ON.
- A98 Front Overhead Console Assembly (-C3U)
- S13D Door Lock Switch - Driver
- S13P Door Lock Switch - Passenger
- S48E Multifunction Switch - Center Console (F45/UHX&UGN/UD5&UD7)
2. Place the interior backlighting dimmer switch in the HIGH position for
high backlighting
intensity.
3. Verify a test lamp illuminates between the appropriate control circuit
terminal listed below and
ground.
- A98 Front Overhead Console Assembly terminal 18 (-C3U)
- S13D Door Lock Switch - Driver terminal 5
- S13P Door Lock Switch - Passenger terminal 5
- S48E Multifunction Switch - Center Console terminal 3 (F45/UHX&UGN/UD5&UD7)
- If the test lamp does not illuminate
- Ignition OFF, disconnect the X1 harness connector at the K9 Body Control
Module.
- Test for infinite resistance between the control circuit 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.
- Go to next step: If the test lamp illuminates
4. Place the interior backlighting dimmer switch in the LOW position for low
backlighting intensity.
5. Verify a test lamp does not illuminate at FULL intensity between the
appropriate control circuit
listed below and ground.
- A98 Front Overhead Console Assembly terminal 18 (-C3U)
- S13D Door Lock Switch - Driver terminal 5
- S13P Door Lock Switch - Passenger terminal 5
- S48E Multifunction Switch - Center Console terminal 3 (F45/UHX&UGN/UD5&UD7)
- If the test lamp illuminates at full intensity
- Ignition OFF, disconnect the X1 harness connector at the K9 Body Control
Module, ignition
ON.
- Test for less than 1 V between the control circuit terminal 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 does not illuminate at full
intensity
6. Test or replace the component with the inoperative indicator.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Door Lock Switch Replacement - Driver Side
- Door Lock Switch Replacement - Passenger Front
- Floor Console Accessory Function Switch Replacement
- Roof Console Replacement
- Control Module References for BCM 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.
Diag
SEE MORE:
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.
DTC Descriptor
DT
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