Hazard Lamps Malfunction

Hazard Lamps Malfunction

Diagnostic Instructions

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



Diagnostic Fault Information






Circuit/System Description

The hazard switch signal circuit is referenced from battery voltage by the BCM. When the hazard switch is activated, the signal circuit is grounded through the switch and the signal circuit voltage goes low. The BCM then sends an ON-OFF voltage signal through the fuses to the appropriate turn signal and side repeater lamps or to all of the turn signal fuses for hazard operation.


Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

Interior Lighting Systems Description and Operation (Interior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Programming and Relearning (Programming and Relearning)for scan tool information


Circuit/System Verification

Ignition ON, observe the scan tool hazard lamp switch parameter while operating the hazard switch on and off. The reading should change between active and inactive.


Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Verify that a test lamp illuminates between the ground circuit terminal C and ground.

• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool hazard lamp switch parameter is Inactive.

• If not the specified value, test the signal circuit terminal G for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal G and the ground circuit terminal C. Verify the scan tool hazard lamp switch parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the turn signal/multifunction switch



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Turn Signal Multifunction Switch Replacement (Turn Signal Multifunction Switch Replacement)
* Programming and Relearning (Programming and Relearning)for BCM replacement, programming, and setup