Hazard Lamps Malfunction

Hazard Lamps Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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/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 lamps or to all of the turn signal fuses for hazard operation.

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 harness connector X1 at the turn signal/multifunction switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal C and ground.

^ If greater than the specified range, 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 after completing the diagnostic procedure. Verification Tests

* Turn Signal Multifunction Switch Replacement