• | 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 |
---|---|---|---|---|
Headlamp Switch Off | B257A 00 | B257A 00 | B257A 00 | -- |
Park Lamp Switch On | B257A 00 | B2057A 00 | B257A 00 | -- |
Headlamp Switch On | 1 | 2 | B2575 00 | -- |
Headlamp Ground | -- | B257A 00 | 2 | -- |
|
When the headlamp switch is in the OFF position, the body control module (BCM) receives a ground signal through the headlamp switch OFF circuit and an open signal on the park lamp ON circuit. When the headlamp switch is in the PARK or HEAD position, the BCM receives an open signal through the headlamp switch OFF circuit and a ground signal through the park lamp ON circuit.
The ignition is ON.
The BCM receives an unexpected signal along either the headlamp switch OFF circuit or the park lamp ON circuit.
The BCM disregards the headlamp switch input and defaults to automatic headlamp function.
The BCM clears this code from current when the fault is removed from the system.
Headlights/Daytime Running Lights (DRL) Schematics
Lighting Systems Connector End Views
Ignition ON, headlamp switch to PARK, just the park lamps should illuminate.
⇒ | If the test lamp does not illuminate: |
• | Test for a short to voltage or an open in the headlamp OFF switch circuit. |
• | Test for an open in the headlamp ground circuit. |
• | If the circuit/connections test normal replace the headlamp switch. |
⇒ | If the test lamp illuminates, test for a short to ground in the headlamp OFF switch circuit. If the circuit/connections test normal, replace the headlamp switch. |
⇒ | If the test lamp does not illuminate, test for a short to voltage or an open in the park lamp switch ON circuit. If the circuit/connections test normal, replace the headlamp switch. |
⇒ | If the test lamp does illuminate, test for a short to ground in the park lamp switch ON circuit. If the circuit/connections test normal, replace the headlamp switch. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |