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 signal circuit is momentarily grounded when the hazard switch is pressed. The body control module (BCM) responds to the hazard switch signal input by supplying 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 serial data message to the instrument panel cluster (IPC) 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 Hybrid/EV Battery Pack X1
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. Vehicle in Service Mode, observe the scan tool Hazard Lamps Switch parameter while turning the hazard lamp switch ON and OFF. The parameter 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 turning the hazard lamps switch ON and OFF. The right and left turn signal lamps should flash ON and OFF while the hazard lamps switch is ON and remain OFF when the hazard lamps 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.
Circuit/System Testing
1. Vehicle OFF, disconnect the harness connector at the A20 radio/HVAC controls.
2. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, and wait 2 minutes. Test for less than 5 ohm between the ground circuit terminal 17 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Vehicle in Service Mode, verify the scan tool Hazard Lamps Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 16 for a short to ground. If the circuit tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 16 and the ground circuit terminal 17. 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, replace the A20 radio/HVAC controls.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Radio Control Assembly Replacement Radio Control Assembly Replacement
* Control Module References Programming and Relearning for BCM replacement, setup, and programming