Headlamps Inoperative - Flash to Pass

HEADLAMPS INOPERATIVE - FLASH TO PASS




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
When the turn signal/multifunction switch is placed in the headlamps high beam or flash to pass (FTP) position, ground is applied to the body control module (BCM) through the headlamp high beam signal circuit or the flash to pass switch signal circuit. The BCM then applies ground to the headlamp high beam relay control circuit which energizes the high beam relay, applying battery voltage to the high beam headlamps.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the C2 harness connector at the turn signal/multifunction switch.
2. Connect a 3-amp fused jumper between the flash to pass switch signal circuit and ground at the turn signal/multifunction switch harness connector.
3. Ignition ON, install a scan tool and observe the Flash to Pass Switch parameter. The scan tool parameter should display Active.
- If the scan tool indicates the Flash to Pass Switch parameter is Inactive, repair the flash to pass switch signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
4. Verify that a test lamp illuminates between battery voltage and the flash to pass switch ground circuit at the turn signal/multifunction switch harness connector.
- If the test lamp does not illuminate, repair the flash to pass switch ground circuit for an open/high resistance.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

- Multifunction, Turn Signal Switch Replacement
- Control Module References for BCM replacement, setup, and programming