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	Circuit Function	Short to Ground	Open/Hig Resistance	h Short to Voltage	Signal Performan
111	Signal	1	1	—	1
7543	Control	2	2	2	—
1850	Ground	—	1, 2	—	—
1. Hazard Lamps Malfunction 2. Hazard Warning Switch Backlighting Malfunction

Scan Tool Functions K9 Body Control Module – Scan Tool Data

Data Parameter	Description
Hazard Warning Switch	This data parameter will show the status of the hazard lamp switch as Active/Inactive when the hazard lamp is being pressed/released

Circuit/System Description The hazard lamps may be activated in any power mode. The K9 Body Control Module (BCM) provides the S26 Hazard Warning Switch with signal circuit 111. The S26 Hazard Warning Switch signal circuit is momentarily grounded when the hazard warning switch is pressed. The BCM responds to the hazard warning switch signal input by sending a serial data message to the K219 Lighting Control Module. The Lighting Control Module responds by supplying battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard warning switch is activated, the BCM also sends a serial data message to the instrument cluster requesting both turn signal indicators to be cycled ON and OFF. The S36 Dimmer Switch is used to increase and decrease the brightness of the interior backlighting components. When the instrument panel dimmer switch is placed in the desired brightness position, the BCM receives the signal from the instrument panel dimmer switch. The BCM interprets the signal and applies pulse width modulated (PWM) voltage through control circuit 7543 illuminating the hazard warning switch backlighting to the requested level of brightness. Reference Information Schematic Reference E t i Li ht S h ti Exterior Lights Schematics Interior Lights Dimming Schematics Connector End View Reference Master Electrical Component List 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

Ignition ON.
Verify all left and right turn signal lamps turn ON and OFF while commanding the left and right turn signals ON and OFF with the S78 Turn Signal Switch. ⇒ If one or more turn signal lamps do not turn ON and OFF Refer to Turn Signal Lamps and/or Indicators Malfunction. ⇓ If all turn signal lamps turn ON and OFF
Verify the hazard switch backlighting changes from bright to dim while commanding the backlight dimming from bright to dim with the S36 Dimmer Switch. ⇒ If the hazard warning switch backlighting does not change Refer to Interior Backlighting Malfunction. ⇓ If the hazard warning switch backlighting changes
Verify the Hazard Warning Switch scan tool parameter changes from Active to Inactive when pressing and releasing the hazard lamp switch. ⇒ If the parameter does not change Refer to Circuit/System Testing. ⇓ If the parameter changes
A fault is not currently present and may be an intermittent condition. Circuit/System Testing
Ignition/vehicle OFF, disconnect the S26 Hazard Warning Switch.
Verify a test lamp illuminates between ground circuit terminal 2 and B+. ⇒ If the test lamp does not illuminate 2.1. Repair the open/high resistance on the ground circuit or ground connection. ⇓ If the test lamp illuminates
Ignition on/vehicle in service mode, verify the Hazard Warning Switch scan tool parameter is Inactive. ⇒ If the parameter is not Inactive 3.1. Test circuit 111 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 3.2. Replace the K9 Body Control Module. ⇓ If the parameter is Inactive
Connect a 3 A fused jumper wire between signal circuit terminal 1 and ground.
Verify the Hazard Warning Switch scan tool parameter is Active. ⇒ If the parameter is not Active and the 3 A fuse is OK 5.1. Test circuit 111 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ if an open/high resistance is not found. 5.2. Replace the K9 Body Control Module. ⇒ If the parameter is not Active and the 3 A fuse is open 5.1. Test circuit 111 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 5.2. Replace the K9 Body Control Module. ⇓ If the parameter is Active
Replace the S26 Hazard Warning Switch. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Lighting Component Replacement Reference Control Module References for BCM replacement, programming, and setup