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. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Hazard Switch Signal | 1 | 1 | 1 | -- |
I/P Lamps Dimmer Switch Signal | 2 | 2 | 2 | -- |
Hazard Switch Ground | -- | 1 | -- | -- |
| ||||
Circuit/System Description
The hazard flashers may be activated in any power mode. The hazard switch is permanently grounded through G200. When the hazard switch is placed in the ON position, ground is applied through the hazard switch signal circuit to the body control module (BCM). The BCM supplies battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a GMLAN serial data message to the instrument panel cluster (IPC) requesting both turn signal indicators to be cycled ON and OFF. For more detailed information concerning hazard lamp operation refer to Exterior Lighting Systems Description and Operation .
Reference Information
Schematic Reference
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
Hazard Lamps Malfunction
- Ignition OFF, disconnect the harness connector at the hazard switch.
- Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal A.
- Ignition ON, verify the scan tool hazard lamp switch parameter is INACTIVE.
- Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool hazard lamp switch parameter is ACTIVE.
- If all circuits test normal, test or replace the hazard switch.
| ⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit terminal D for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Hazard Lamp Indicators Malfunction
Ignition ON, with a scan tool perform the display test for the instrument panel cluster (IPC) and observe both turn signal indicators.
| ⇒ | If both turn signal indicators illuminate during the test, replace the BCM. |
| ⇒ | If both turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the IPC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM or IPC replacement, setup, and programming |
