Circuit Description
The body control module (BCM) monitors the instrument panel (I/P) lamps dimming control circuit to determine the lighting intensity of the I/P lamps. When the BCM receives a varied voltage signal on the I/P lamps dimming control circuit, it applies a corresponding pulse width modulation (PWM) voltage signal through the I/P lamps supply voltage circuit to all the I/P lamps.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2627 Display Dimming Pulse Width Modulation (PWM) Output Circuit Low
Conditions for Running the DTC
| • | Voltage supplied to the BCM is in the normal operating range, approximately 9-14 volts. |
| • | The ignition switch must be in the ACCESSORY or RUN position. |
| • | The park lamps must be ON. |
Conditions for Setting the DTC
| • | The BCM detects a short to ground in the I/P lamp supply voltage circuit. |
| • | The above condition must be present for more than 1 second. |
Action Taken When the DTC Sets
| • | The I/P courtesy lamps are inoperative. |
| • | The BCM stores DTC B2627 in memory. |
Conditions for Clearing the MIL/DTC
| • | A current DTC B2627 clears when the BCM no longer detects a short to ground in the I/P lamps supply voltage circuit. |
| • | A history DTC B2627 clears after 100 consecutive ignition cycles. |
Diagnostic Aids
| • | If the DTC B2627 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections . |
| • | The following conditions may cause an intermittent malfunction to occur: |
| - | An intermittent short to ground in the instrument panel lamps supply voltage circuit |
| - | The BCM is intermittently shorted to ground. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics and Interior Lights Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Do the I/P lamps illuminate and vary intensity? | Go to Diagnostic Aids | Go to Step 3 |
3 | Test the I/P lamps supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 5 | Go to Step 4 |
4 | Replace the body control module (BCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 5 | -- |
5 |
Does the DTC reset? | Go to Step 2 | System OK |
