Headlamps Flash to Pass Inoperative

Headlamps Flash to Pass Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The high beam headlamps are controlled by the BCM through the high beam relay. The relay is supplied battery voltage and is energized when the BCM grounds the low side drive control circuit. The flash to pass switch signal circuit is referenced from battery voltage by the BCM and when the switch is activated the signal circuit is grounded, and the BCM determines the switch is active when the signal circuit voltage is low.

Circuit/System Verification

With the headlamps ON, observe the scan tool Flash to Pass Switch parameter while pulling and releasing the flash to pass switch. The parameter should cycle between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector X2 at the turn signal/multifunction switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal D and ground.

^ If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Flash to Pass Switch parameter is Inactive.

^ If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal A and the ground circuit terminal D. Verify the scan tool Flash to Pass 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 BCM.

5. If all circuits test normal, test or replace the signal/multifunction switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Turn Signal Multifunction Switch Replacement