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: Dimming Display Pulse Width Modulation (PWM) Input Circuit LowDTC B2623: Dimming Display Pulse Width Modulation (PWM) Input Circuit High
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
LR Park Lamp B+ | 1 | 1 | -- | -- |
I/P Dimmer Switch Signal | 2 | 2 | 2 | -- |
I/P Backlight Signal | 2 | 2 | 2 | -- |
LED Backlight Dimming Control | 1 | 1 | 1 | -- |
Accessory Lamp Backlighting Control | B2622 | 1 | B2623 | -- |
Hazard Switch Backlighting Control | B2622 | 1 | B2623 | -- |
HVAC Control Module Backlighting Control | B2622 | 1 | B2623 | -- |
I/P Dimmer Switch Backlighting Control | B2622 | 1 | B2623 | -- |
Radio Backlighting Control | B2622 | 1 | B2623 | -- |
Rear Window Wiper/Washer Switch Backlighting Control | B2622 | 1 | B2623 | -- |
Sunroof Switch Backlighting Control | B2622 | 1 | B2623 | -- |
Accessory Lamp Backlighting Ground | -- | 1 | -- | -- |
Hazard Switch Backlighting Ground | -- | 1 | -- | -- |
HVAC Control Module Backlighting Ground | -- | 1 | -- | -- |
I/P Dimmer Switch Backlighting Ground | -- | 1 | -- | -- |
Radio Backlighting Ground | -- | 1 | -- | -- |
Rear Window Wiper/Washer Switch Backlighting Ground | -- | 1 | -- | -- |
Sunroof Switch Backlighting Ground | -- | 1 | -- | -- |
I/P Dimmer Switch Low Reference | -- | 2 | -- | -- |
1. Interior Backlighting Malfunction 2. Interior Backlighting Switch Malfunction | ||||
Circuit/System Description
The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the I/P controls illumination lamps to a desired intensity. When this occurs, the BCM directly sends a variable voltage based on the I/P dimmer switch position through the I/P lamps supply voltage circuit to the I/P controls illumination lamps.
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
B2622
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
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 harness connector at the inoperative interior backlighting lamp.
- Verify that a test lamp illuminates between the listed component ground circuit and B+.
- Ignition OFF, park lamps ON, verify that a test lamp illuminates between the listed control circuit terminal and ground.
- If all circuits test normal, replace the component with the inoperative backlighting.
| • | Accessory switch terminal 13 |
| • | Hazard switch terminal B |
| • | HVAC control module terminal C |
| • | Rear window wiper/washer switch terminal A |
| • | Radio terminal B5 X1 |
| • | Sunroof switch terminal C |
| • | Headlamp switch terminal 3 |
| ⇒ | If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance. |
| • | Accessory switch terminal 12 |
| • | Hazard switch terminal A |
| • | HVAC control module terminal D |
| • | Rear window wiper/washer switch terminal D |
| • | Radio terminal B4 X1 |
| • | Sunroof switch terminal B |
| • | Headlamp switch terminal 6 |
| ⇒ | If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM. |
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. 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, HVAC control module, or radio replacement, programming, and setup |
