Pinpoint Test C: The Low Beam(s) Are Always On
Headlamps
Pinpoint Test C: The Low Beam(s) Are Always On
Normal Operation
The Steering Column Control Module (SCCM) sends voltage signals to the headlamp switch through the headlamp switch input circuits (off, parking lamps, headlamps). At any given time, the headlamp switch routes one of the input circuits to ground, indicating the headlamp switch position to the SCCM (Steering Column Control Module). The SCCM (Steering Column Control Module) sends a message over the High Speed Controller Area Network (HS-CAN) to the BCM (Body Control Module) to indicate the headlamp switch position. When the BCM (Body Control Module) receives a message from the SCCM (Steering Column Control Module) indicating the headlamp switch in the HEADLAMPS ON position, the BCM (Body Control Module) provides voltage to the LH and RH low beams.
If the SCCM (Steering Column Control Module) detects multiple or no active headlamp switch inputs, the BCM (Body Control Module) receives a message from the SCCM (Steering Column Control Module) indicating a fault with the headlamp switch input and the BCM (Body Control Module) defaults the exterior lamps on.
If the BCM (Body Control Module) loses communication with the SCCM (Steering Column Control Module), the BCM (Body Control Module) defaults the exterior lamps on.
- DTC B10A6:09 (Main Light Switch: Component Failure)- a continuous and on-demand DTC that sets when the SCCM (Steering Column Control Module) detects a fault from the headlamp switch input circuit(s).
- DTC B1D00:15 (Left Low Beam: Circuit Short To Battery or Open)- a DTC that sets when the BCM (Body Control Module) detects a short to voltage from the LH low beam output circuit.
- DTC B1D01:15 (Right Low Beam: Circuit Short To Battery or Open)- a DTC that sets when the BCM (Body Control Module) detects a short to voltage from the RH low beam output circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Headlamp switch
- SCCM (Steering Column Control Module)
- BCM (Body Control Module)
PINPOINT TEST C : THE LOW 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.
C1 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Network Test.
- Carry out the network test.
Does the SCCM (Steering Column Control Module) module pass the network test?
Yes
If equipped with autolamps, GO to C2.
If not equipped with autolamps, GO to C4.
No
REFER to Information Bus.
C2 CHECK FOR LIGHT SENSOR DTCs
- Review the DTCs recorded from the BCM (Body Control Module) self-test.
Is DTC B1A85:11 or DTC B1A85:13 present?
Yes
GO to Pinpoint Test H Pinpoint Test H: The Autolamps Are On Continuously.
No
GO to C3.
C3 CHECK THE SCCM (Steering Column Control Module) AUTOLAMP ON REQUEST PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SCCM (Steering Column Control Module) DataLogger.
- While placing the headlamp switch in the AUTOLAMPS ON and then OFF position, monitor the SCCM (Steering Column Control Module) headlamp switch PID.
Does the PID indicate ON with the headlamp switch in the AUTOLAMPS ON position and OFF when the headlamp switch is in the OFF position?
Yes
GO to C4.
No
GO to Pinpoint Test H Pinpoint Test H: The Autolamps Are On Continuously.
C4 CHECK THE SCCM (Steering Column Control Module) HEADLAMP SWITCH PIDs
NOTE: Make sure the headlamp switch is aligned in the correct position when monitoring the PIDs.
NOTE: Only one PID should indicate ON at each headlamp switch position.
- Enter the following diagnostic mode on the scan tool: SCCM (Steering Column Control Module) DataLogger.
- While moving the headlamp switch through all positions (OFF, PARKING LAMPS and HEADLAMPS), monitor the SCCM (Steering Column Control Module) headlamp switch input PIDs.
Do the headlamp switch positions agree with the PIDs (with only one PID indicating ON in each position?
Yes
GO to C9.
No
GO to C5.
C5 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH INPUT CIRCUITS
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Measure the voltage between the headlamp switch, harness side and ground as follows:
Headlamp Switch Connector-Pin Circuit C205-6 CLF23 (WH/VT) C205-2 CLF34 (YE/OG) C205-7 CLF24 (YE/BU)
Are the voltages greater than 5 volts?
Yes
GO to C6.
No
GO to C7.
C6 CHECK THE HEADLAMP SWITCH GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between the headlamp switch C205-6, circuit CLF23 (WH/VT), harness side and headlamp switch C205-3, circuit GD184 (BK/GY or BK/YE), harness side.
Is the voltage greater than 5 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch . TEST the system for normal operation.
No
REPAIR circuit GD184 (BK/GY or BK/YE) for an open. TEST the system for normal operation.
C7 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR A SHORT TO GROUND
- Disconnect: SCCM (Steering Column Control Module) C2414A.
- Measure the resistance between the headlamp switch, harness side and ground as follows:
Headlamp Switch Connector-Pin Circuit C205-6 CLF23 (WH/VT) C205-2 CLF34 (YE/OG) C205-7 CLF24 (YE/BU)
Are the resistances greater than 10,000 ohms?
Yes
GO to C8.
No
REPAIR the circuit in question for an open. TEST the system for normal operation.
C8 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR AN OPEN
- Measure the resistance between the headlamp switch, harness side and the SCCM (Steering Column Control Module), harness side as follows:
Headlamp Switch Connector-Pin SCCM (Steering Column Control Module) Connector-Pin Circuit C205-6 C2414A-21 CLF23 (WH/VT) C205-2 C2414A-22 CLF34 (YE/OG) C205-7 C2414A-18 CLF24 (YE/BU)
Are the resistances less than 5 ohms?
Yes
GO to C10.
No
REPAIR the circuit in question for an open. TEST the system for normal operation.
C9 CHECK THE BCM (Body Control Module) OUTPUT
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280E.
- Ignition ON.
Does the LH or RH headlamp continue to illuminate?
Yes
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN or BN/GN) (RH headlamp) for a short to voltage as necessary. TEST the system for normal operation.
No
GO to C11.
C10 CHECK FOR CORRECT SCCM (Steering Column Control Module) OPERATION
- Disconnect all the SCCM (Steering Column Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SCCM (Steering Column 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 SCCM (Steering Column 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.
C11 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.