Circuit Description
The body control module (BCM) controls the illumination of the following lamps through pulse width modulation when the park lamps or the headlamps are ON:
| • | The automatic transmission control position illumination lamp |
| • | The left glass window release switch illumination lamp |
| • | The electronic traction control switch illumination lamp |
| • | The door lock theft deterrent defeat switch illumination lamp |
| • | The heater A/C control switch illumination lamp |
| • | The instrument cluster illumination lamps |
| • | The headlamp switch illumination lamp |
| • | The radio switches illumination lamps |
| • | The driver information display switch illumination lamp |
| • | The heated seat switch illumination lamp |
| • | The door lock switches illumination lamps |
| • | The window switches illumination lamps |
| • | The steering wheel controls illumination lamps |
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2628 Display Dimming Pulse Width Modulation Output Circuit High
Conditions for Running the DTC
Voltage supplied to the module is in the normal operating range, approximately 10-16 volts.
Conditions for Setting the DTC
| • | The BCM detects a short to voltage in the instrument panel lamps supply voltage circuit. When the park lamps or the headlamps are ON, and the dimmer switch is in the OFF position. |
| • | The condition is present for more than 3 ms. |
Action Taken When the DTC Sets
The BCM stores DTC B2628 in memory.
Conditions for Clearing the MIL/DTC
| • | A current DTC B2628 clears if the BCM no longer detects a short to battery positive voltage in the instrument panel lamps supply voltage circuit of the illumination lamps. |
| • | A history DTC B2628 clears after 100 consecutive ignition cycles if the condition is no longer present. |
| • | The BCM receives the Clear Code command from the scan tool. |
Diagnostic Aids
| • | If the DTC B2628 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections . |
| • | An intermittent short to voltage in the following conditions may cause an intermittent malfunction to occur: |
| - | The instrument panel lamps supply voltage circuit of the illumination lamps |
| - | The BCM |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 | Do the instrument panel lamps turn ON with the headlamp switch in the PARK position? | Go to Diagnostic Aids | Go to Step 3 |
3 |
Do the test lamp illuminate? | Go to Step 4 | Go to Step 5 |
4 | Repair a short to battery positive voltage in the instrument panel lamps supply voltage circuit of the illumination lamps. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 6 | -- |
5 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 6 | -- |
6 |
Does the DTC reset? | System OK | Go to Step 3 |
