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 Control | 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
Description and Operation
Interior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
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 |
