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 B2622 00: Dimming Display Pulse Width Modulation (PWM) Input Circuit LowDTC B2623 00: Dimming Display Pulse Width Modulation (PWM) Input Circuit High
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Body Control Module B+ | B2622 00 | B2622 00 | B2622 00 | -- |
I/P Lamps Dimmer Switch Signal | B2622 00 | 2 | B2623 00 | -- |
Accessory Switch Control | B2622 00 | 1 | B2623 00 | -- |
Hazard Switch Control | B2622 00 | 1 | B2623 00 | -- |
HVAC Control Module Control | B2622 00 | 1 | B2623 00 | -- |
I/P DImmer Control | B2624 00 | B2624 00 | B2624 00 | -- |
Accessory Switch Ground | -- | 1 | -- | -- |
Hazard Switch Ground | -- | 1 | -- | -- |
HVAC Control Module Ground | -- | 1 | -- | -- |
Headlamp and Panel DImmer Switch Low Reference | 2 | 2 | 2 | -- |
| ||||
Circuit/System Description
The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
B2622 00
When the BCM receives an I/P controls illumination lamp request signal and the I/P lamps supply voltage circuit is shorted to ground.
B2623 00
When the BCM is not receiving an I/P controls illumination lamp request signal and the I/P lamps supply voltage circuit is shorted to voltage.
Action Taken When the DTC Sets
The I/P controls illumination lamps will not operate or are always on.
Conditions for Clearing the DTC
| • | This DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
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 BCM connector X2.
- Ignition ON, verify that the following components backlighting is not illuminated.
- Connect a fused jumper wire from B+ to the following terminals and verify associated backlighting operation.
- If all circuits test normal, replace the BCM.
| • | Hazard switch |
| • | HVAC control module terminal |
| • | Headlamp switch |
| ⇒ | If any of the listed components backlighting is illuminated, test the associated control circuit for a short to voltage. |
| • | Hazard switch A28 |
| • | HVAC control module terminal A29 |
| • | Headlamp switch A36 |
| ⇒ | If the jumper fuse opens while connected to any of the listed terminals, test the associated control circuit for a short to ground. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BCM replacement, programming, and setup.
