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

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.

Schematic Reference

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References

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.

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