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.
The I/P dimmer switch controls are located on the headlamp switch assembly and are used to increase and decrease the brightness of the interior backlighting components. When the I/P dimmer switch is placed in a desired brightness position, the body control module (BCM) receives a signal from the I/P dimmer switch and responds by applying a pulse width modulated (PWM) voltage to the hazard switch light emitting diode (LED) backlighting control circuit illuminating the LED to the desired level of brightness.
Reference Information
Schematic Reference
Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left (D6I)
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, 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 Hazard Lamps Switch Malfunction.
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
3. Command the Hazard Lamps Switch Backlight ON and OFF with a scan tool. The hazard lamps switch backlighting should turn ON and OFF when changing between the commanded states.
• If the hazard lamps switch backlighting does not turn ON and OFF, refer to Hazard Lamps Switch Backlighting Malfunction.
Circuit/System Testing
Hazard Lamps Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the S26 hazard lamps switch.
2. Ignition 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 3 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 1 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 1 and the ground circuit terminal 3. 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 S26 hazard lamps switch.
Hazard Lamps Switch Backlighting Malfunction
1. Ignition OFF, disconnect the harness connector at the S26 hazard lamps switch.
2. Ignition 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 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal 2 and ground.
4. Ignition ON, command the Hazard Lamps Switch Backlight ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, replace the S26 hazard lamps switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Hazard Warning Switch Replacement Service and Repair
* Control Module References Control Module References for BCM replacement, setup, and programming