GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The driver door module (DDM) and the passenger door module (PDM) receive a discrete input from the driver door ajar switch and the passenger door ajar switch respectively. Likewise, the body control module (BCM) receives a discrete input from both the left and right rear door ajar switches. The door ajar switches are normally open when the doors are fully closed. When a door is opened, the door ajar switch contacts close providing a path to ground. The driver information center (DIC) located at the bottom of the instrument panel cluster (IPC), illuminates the appropriate door ajar message when one of the doors is open. The IPC receives a class 2 serial data message from the BCM, DDM, or PDM indicating the door ajar status. If this message is displayed and the vehicle speed is greater than 8.1 km/h (5 mph), a chime will sound.

Reference Information

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Displays and Gages Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

  1. Ignition ON, open and close the driver and passenger doors. Check to see if the courtesy lamps are operating properly.
  2. If the courtesy lamps are not operating properly, refer to Courtesy Lamps Always On and Courtesy Lamps Inoperative .
  3. If the courtesy lamps are operating properly, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for the IPC replacement, setup, and programming