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 flashers may be activated in any power mode. The hazard switch is permanently grounded. 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 turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a serial data message to the instrument cluster requesting both turn signal indicators to be cycled ON and OFF.
Reference Information
Schematic Reference
Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Exterior Lighting Systems Description and Operation Exterior Lighting Systems
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Hazard Lamps Switch parameter while applying and releasing the hazard switch. The reading should change between Active and Inactive.
• If the parameter does not change between the commanded states, refer to Circuit/System Testing.
2. Observe the right and left turn signal lamps while applying and releasing the hazard lamp switch. The right and left turn signal lamps should flash ON and OFF while the hazard lamp switch is ON and remain OFF when the hazard lamp switch is OFF.
• If the turn signal lamps do not cycle between the selected states, refer to Turn Signal Lamps and/or Indicators Malfunction Turn Signal Lamps and/or Indicators Malfunction.
3. Command the All Indicators Test ON and OFF with a scan tool. The left and right turn signal indicators should turn ON and OFF when changing between the commanded states.
• If the left and right turn signal indicators illuminate during the test, replace the K9 BCM.
• If the left and right turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the P16 instrument panel cluster.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the S48C multifunction switch 1-instrument panel.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 ohms between the ground circuit terminal 7 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 Lamps Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 10 for a short to ground. If the circuits tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 10 and the ground circuit terminal 7. Verify the scan tool Hazard Lamps 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 K9 BCM.
5. If all circuits test normal, test or replace the S48C multifunction switch 1-instrument panel.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Hazard Warning Switch Replacement Service and Repair
* Control Module References Programming and Relearning for BCM or instrument cluster replacement, programming and setup