GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this 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

Voltage is supplied to the instrument panel cluster (IPC) through the battery voltage circuit and the RUN/CRANK relay voltage circuit. The IPC will operate when the RUN/CRANK relay voltage circuit is commanded on in the RUN/START position.

Reference Information

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the IPC.
  2. Ignition ON, verify that a test lamp illuminates between the following RUN/CRANK relay voltage circuits listed below and a ground.
  3. • RUN/CRANK Relay Terminal 2 (Z75)
    • RUN/CRANK Relay Terminal 5 (X88/Z88)
    If the test lamp does not illuminate, repair the RUN/CRANK voltage circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the following RUN/CRANK relay voltage circuit(s) and ground circuit(s) listed below:
  5. • RUN/CRANK Relay Terminal 2 (Z75)
    • RUN/CRANK Relay Terminal 5 (X88/Z88)
    • Ground Terminal 5 (Z75)
    • Ground Terminal 13 (X88/Z88)
    If the test lamp does not illuminate, repair the IPC ground circuit for an open/high resistance.
  6. If all circuits test normal, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for IPC replacement, setup, and programming