For 1990-2009 cars

### Diagnostic Fault Information

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

### Circuit/System Description

The instrument panel cluster generates the audible warning. The IPC receives audible warning requests via GMLAN serial data from the body control module (BCM) and/or other modules.

### Reference Information

#### Schematic Reference

• | Instrument Cluster Schematics

• | Body Control System Schematics

• | Steering Wheel Secondary/Configurable Control Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Testing

1. Ignition ON, headlamp switch OFF, using a scan tool verify the Headlamp Switch parameter is Inactive.

⇒ | If not Inactive, test the headlamps signal circuit for an open/high resistance or short to voltage. If the circuit tests normal, replace the headlamp switch.

2. Ignition ON, park lamp switch OFF, Using a scan tool verify the Park Lamp Switch parameter is Inactive.

⇒ | If not Inactive, test the park lamp switch signal circuit for an open/high resistance or short to voltage. If the circuit tests normal, replace the headlamp switch.

3. Ignition OFF, key out of the ignition, using a scan tool verify the Key In Ignition Status parameter is Key Out.

⇒ | If not Key Out, test the key in ignition switch signal circuit for an open/high resistance or short to voltage. If the circuit tests normal, replace the ignition switch.

### Repair Instructions

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

• | Ignition and Start Switch Replacement

• | Turn Signal Switch Replacement

• | Control Module References for BCM replacement, setup, and programming