Pinpoint Test D: The High Beam(s) Are Always On
Headlamps
Pinpoint Test D: The High Beam(s) Are Always On
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information Electrical Diagrams.
Normal Operation
The Steering Column Control Module (SCCM) monitors input from the multifunction switch. When the multifunction switch is placed in the FLASH-TO-PASS position (first detent when pulled towards the operator) or the headlamp switch is in the HEADLAMPS ON position and the multifunction switch is placed in the HIGH BEAM position (second detent), the SCCM (Steering Column Control Module) sends a message over the High Speed Controller Area Network (HS-CAN) to the Body Control Module (BCM), indicating a flash-to-pass or high beam request. The BCM (Body Control Module) then provides voltage to the high beam shutters within the headlamp assemblies. The shutters are held in their normal (low beam) position by springs.
The multifunction switch returns to a rest position when released. The switch positions for the flash-to-pass and high beam features are momentary contact.
- DTC B1007:09 (High-Beam Headlamp Switch: Component Failure)- a DTC that sets when the SCCM (Steering Column Control Module) detects a fault from the multifunction switch input.
- DTC B1D02:15 (Left High Beam Circuit: Circuit Short To Battery or Open)- a DTC that sets when the BCM (Body Control Module) detects a short to voltage from the LH high beam output circuit.
- DTC B1D03:15 (Right High Beam Circuit: Circuit Short To Battery or Open)- a DTC that sets when the BCM (Body Control Module) detects a short to voltage from the RH high beam output circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Multifunction switch
- SCCM (Steering Column Control Module)
- BCM (Body Control Module)
PINPOINT TEST D : THE HIGH BEAM(S) ARE ALWAYS ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
D1 CHECK THE MULTIFUNCTION SWITCH INPUT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SCCM (Steering Column Control Module) DataLogger.
- Monitor the SCCM (Steering Column Control Module) multifunction switch flash-to-pass and high beam PIDs (FLASH-to-PASS, HIGH_BEAM_SW) while placing the multifunction switch in the FLASH-TO-PASS, HIGH BEAM and REST positions.
Do the PID values agree with the multifunction switch position?
Yes
GO to D2.
No
INSTALL a new multifunction switch. TEST the system for normal operation.
If the concern still exists, INSTALL a new SCCM (Steering Column Control Module). TEST the system for normal operation.
D2 CHECK THE BCM (Body Control Module) HIGH BEAM OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280E.
- Ignition ON.
Do the high beams continue to illuminate?
Yes
GO to D3.
No
GO to D4.
D3 CHECK FOR VOLTAGE TO THE HEADLAMP
- Ignition OFF.
- Disconnect: Inoperative Headlamp.
- Ignition ON.
- Measure the voltage between the LH headlamp C1021A-3, circuit CLF02 (GY/BN), harness side and ground; or between the RH headlamp C1041A-3, circuit CLF03 (VT/OG), harness side and ground.
Is any voltage present?
Yes
REPAIR circuit CLF02 (GY/BN) (LH high beam) or circuit CLF03 (RH high beam) for a short to voltage. TEST the system for normal operation.
No
INSTALL a new headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation.
D4 CHECK FOR CORRECT BCM (Body Control Module) OPERATION
- Disconnect all the BCM (Body Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM (Body Control Module) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.