• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Flash to Pass Switch Signal | 1 | 5 | 5 | -- |
Headlamp High Beam Relay Control | B2580 06 | B2580 06 | B2580 01 | -- |
Headlamp Dimmer Switch High Beam Signal | 1 | 2 | 2 | -- |
Headlamp Switch Headlamps On Signal | 1 | 4 | 4 | -- |
Headlamp Switch Headlamps Off Signal | 4 | 1 | 1 | -- |
Headlamp Switch Signal | 1 | 4 | 4 | -- |
Low Beam Relay Control | 1 | 3 | 3 | -- |
LF High Beam Headlamp Voltage Supply | 2 | 2 | 1 | -- |
LF Low Beam Headlamp Voltage Supply | 3 | 3 | 1 | -- |
RF High Beam Headlamp Voltage Supply | 2 | 2 | 1 | -- |
RF Low Beam Headlamp Voltage Supply | 3 | 3 | 1 | -- |
LF Headlamp Ground | -- | 4 | 4 | -- |
RF Headlamp Ground | -- | 4 | 4 | -- |
Turn Signal/Multifunction Switch Ground | -- | 4 | 4 | -- |
1. Headlamps Always On - Low or High Beams 2. Headlamps Inoperative - High Beams 3. Headlamps Inoperative - Low Beams 4. Headlamps Inoperative - Low and High Beams 5. Headlamps Inoperative - Flash to Pass |
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.
Headlights/Daytime Running Lights (DRL) Schematics
Lighting Systems Connector End Views
⇒ | 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. |
⇒ | If the test lamp does not illuminate, repair the flash to pass switch ground circuit for an open/high resistance. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |