Circuit Description
The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the dimming lamps to a desired intensity. When this occurs, the BCM directly sends a pulse width modulated (PWM) voltage based on the I/P dimmer switch position on the LED dimming supply circuit, instrument panel lamps dimming control circuit, and the instrument panel lamps dimming supply voltage circuit.
Voltage for the LED dimming supply circuit, instrument panel lamps dimming control circuit, and the instrument panel lamps dimming supply voltage circuit is from the INADV/PWR/LED 20A fuse in the I/P fuse block directly through the BCM to these circuits.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2625 Display Dimming Pulse Width Modulation (PWM) Output Circuit
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | The instrument panel lamps dimming control circuit is shorted to ground. |
| • | The LED dimming supply circuit is shorted to ground. |
| • | There is a loss of the I/P fuse block INADV/PWR/LED 20A fuse battery supply voltage to the BCM for 1 second. |
Action Taken When the DTC Sets
All dimming lamps will not illuminate or the control switch ON/OFF indicators will not illuminate.
Conditions for Clearing the MIL/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. |
| • | History and current DTCs can be cleared using a scan tool. |
Diagnostic Aids
| • | Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections . |
| • | A short to ground in the following circuits will cause the INADV/PWR/LED 20A fuse to open. |
| - | The instrument panel lamps dimming control. |
| - | Battery positive voltage from the I/P fuse block INADV/PWR/LED 20A fuse. |
| • | An open in the INADV/PWR/LED 20A fuse will cause the BCM to set the following DTC: |
| - | B2610 |
| - | B2625 |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||
2 | Test the following circuits for a short to ground:
Did you find and correct the condition? | Go to Step 5 | Go to Step 3 | ||||||
3 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 5 | Go to Step 4 | ||||||
Replace the BCM. Refer to Control Module References . Did you complete the replacement? | Go to Step 5 | -- | |||||||
5 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||
