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Hazard Lamps Malfunction

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • 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

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Hazard Lamps Switch Signal

1

1

1

B3596 00

Hazard Lamps Switch Ground

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1

--

--

1. Hazard Lamps Malfunction

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 indicator 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 requesting both indicator indicators to be cycled ON and OFF.

Reference Information

Schematic Reference

Exterior Lamps Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References 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.
  2. If the parameter does not change between the commanded states, refer to Circuit/System Testing.
  3. Observe the right and left indicator lamps while turning the hazard lamps switch ON and OFF. The right and left indicator lamps should flash ON and OFF while the hazard lamps switch is ON and remain OFF when the hazard lamps switch is OFF
  4. If the indicator lamps do not cycle between the selected states, refer to Indicator 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 Ω between the ground circuit terminal 17 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Vehicle in Service Mode, verify the scan tool Hazard Lamps Switch parameter is Inactive.
  5. If not the specified value, test the signal circuit terminal 16 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.
  6. 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.
  7. 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 Body Control Module.
  8. If all circuits test normal, replace the A20 Radio/HVAC Controls.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Radio Control Assembly Replacement
    • Control Module References for BCM replacement, programming and setup
   


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