Actions Taken When the DTC Sets
* The low beam headlamps are always ON in the AUTO position. The headlamp switch operates in all positions other than AUTO. The AUTO
headlamp defeat is inoperative.
* The low beam headlamps are always ON. The BCM disregards all headlamp switch inputs.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System
Diagram/Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Exterior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Exterior Lighting Systems Description
and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the X2 harness connector at the BCM.
2. Connect a test lamp between B+ and the signal circuit terminal 17.
3. Turn the headlamp switch between the AUTO and AUTO disable positions. The test lamp should turn ON and OFF as the switch is cycled.
锟斤拷 If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the
headlamp and panel dimmer switch.
锟斤拷 If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the headlamp and panel dimmer
switch.
4. Connect a test lamp between B+ and the signal circuit terminal 3.
5. Turn the headlamp switch to the ON and OFF positions. The test lamp should turn ON and OFF as the switch is cycled.
锟斤拷 If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the
headlamp and panel dimmer switch.
锟斤拷 If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit test normal, replace the headlamp and panel dimmer
switch.
6. If all circuits test normal, replace the BCM.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Headlamp Switch Replacement (Cadillac) (See: Lighting and Horns/Headlamp/Headlamp Switch/Service and Repair/Headlamp Switch
Replacement (Cadillac))Headlamp Switch Replacement (Except Cadillac) (See: Lighting and Horns/Headlamp/Headlamp Switch/Service
and Repair/Headlamp Switch Replacement (Except Cadillac))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming
