Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

When the interior lamps dimming switch is activated, a variable voltage signal is applied through the instrument panel lamps dimmer switch signal circuit to the body control module (BCM). The BCM then applies a variable voltage signal through the LED indicator dimming supply circuit to the following components:

The ignition is ON.

The BCM receives a ground signal on the LED indicator dimming supply circuit.

The BCM cease attempt to dim or illuminate the LED indicator lamps.

The BCM clears this code from current when the fault is removed from the system.

Schematic Reference

Interior Lights Dimming Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

Scan Tool Reference

Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The LED lamps should dim and then become full bright.

1. Disconnect all the LED indicator dimming supply circuit lamps related components. Refer to the circuit/system verification for all components that contain the LED indicator dimming supply circuit lamps. Verify DTC B2625 does not set.

⇒	If the DTC resets, then test for a short to ground in the LED indicator dimming supply circuit lamps circuit. If the circuit/connections test normal, replace the BCM.

2. Reconnect each component one at a time and test for the DTC B2625. If the DTC resets, then replace that component.

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.