For 1990-2009 cars

### 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 modulated (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 B2625 Display Dimming Pulse Width Modulation (PWM) Output Circuit

### 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 instrument panel 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 store DTC B2625 in memory.

### Conditions for Clearing the MIL/DTC

• | A current DTC B2625 clears when the BCM no longer detects a short to ground in the I/P lamps supply voltage circuit.

• | A history DTC B2625 clears after 100 consecutive ignition cycles.

### Diagnostic Aids

• | If the DTC B2625 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 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn the ignition to the ON position.
2. Place the headlamp switch in the park position.
3. Operate the instrument panel (I/P) dimmer switch from full dim to full bright.

The I/P lamps illuminate and vary intensity?

Go to Testing for Intermittent Conditions and Poor Connections

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 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK