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 B2624: Dimming Display Pulse Width Modulation (PWM) Input Circuit OpenDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
I/P Dimmer Switch Signal | B2624 | 1 | B2624 | -- |
I/P Dimmer Switch Voltage Reference | 1 | 1 | B2624 | -- |
I/P Dimmer Switch Low Reference | -- | 1 | -- | -- |
1. Interior Backlighting Malfunction | ||||
Circuit/System Description
The body control module (BCM) directly sends a reference voltage to the instrument panel (I/P) dimmer switch which is then reduced based on the I/P dimmer switch position and monitored as a signal to the BCM. The BCM uses this signal to directly control the desired level of I/P illumination lamp intensity.
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | The BCM detects a short to voltage or an open/high resistance in the I/P dimmer switch signal circuit. |
| • | The BCM detects a short to voltage in the I/P dimmer switch voltage reference circuit. |
Action Taken When the DTC Sets
Interior backlighting will be inoperative or will not dim with the I/P dimmer switch depending on what fault is present.
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 Schematics
Connector End View Reference
Lighting Systems Connector End Views
Description and Operation
Interior Lighting Systems Description and Operation
Electrical Information Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the headlamp switch.
- Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal 3.
- Ignition ON, verify that the scan tool Dimming Potentiometer parameter is greater than 9.0 volts.
- Install a 3A fused jumper wire between the signal circuit terminal 14 and ground. Verify the scan tool Dimming Potentiometer is less than 1.0 volt.
- If all circuits test normal, test or replace the headlamp switch.
| ⇒ | If the test lamp does not illuminate, test the low reference circuit for a short to ground or an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal 14 for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, programming, and setup |
