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Pinpoint Test H: The Autolamps Are On Continuously




Autolamps

Pinpoint Test H: The Autolamps Are On Continuously

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, autolamps). 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 the status of the headlamp switch position to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN).

The autolamp feature is enabled when the BCM (Body Control Module) receives a message from the SCCM (Steering Column Control Module) indicating the headlamp switch in the AUTOLAMPS ON position.

When the BCM (Body Control Module) enables the autolamps feature, the BCM (Body Control Module) monitors the light sensor input. The light sensor determines the amount of light based on the input received from the ambient lighting conditions. When the ambient level has reached a point (determined by the internal programming of the BCM (Body Control Module) ), the BCM (Body Control Module) provides voltage to the exterior lamps.

If the SCCM (Steering Column Control Module) detects multiple or no active headlamp switch inputs, it sends a message to the BCM (Body Control Module) to indicate a fault with the headlamp switch input.

The BCM (Body Control Module) defaults the exterior lamps on when the BCM (Body Control Module) detects any of the following conditions:

- a fault with the light sensor input

- a message from the SCCM (Steering Column Control Module) indicating a fault with the headlamp switch input

- the BCM (Body Control Module) loses communication with the SCCM (Steering Column Control Module)

Autolamp System DTCs

- DTC B1A85:11 (Ambient Light Sensor: Circuit Short To Ground)- This DTC sets when the BCM (Body Control Module) detects a short to ground from the light sensor input circuit.

- DTC B1A85:13 (Ambient Light Sensor: Circuit Open)- This DTC sets when the BCM (Body Control Module) detects an open or short to voltage from the light sensor input circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Light sensor

- Headlamp switch

- SCCM (Steering Column Control Module)

- BCM (Body Control Module)

PINPOINT TEST H : THE AUTOLAMPS ARE ON CONTINUOUSLY

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE:
Make sure the HVAC control operates correctly before diagnosing the autolamp system.

H1 CHECK THE SCCM (Steering Column Control Module) AUTOLAMP ON REQUEST PID
NOTE: Make sure the headlamp switch is lined up in the correct position when monitoring the 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 (EXT_LMP_SW).

Does the PID agree with the headlamp switch when it is in the AUTOLAMPS ON position and indicate it is not in the AUTOLAMPS ON position when the headlamp switch is in the OFF position?

Yes
GO to H5.
No
GO to H2.

H2 CHECK FOR A VOLTAGE SIGNAL TO THE HEADLAMP SWITCH

- Ignition OFF.

- Disconnect: Headlamp Switch C205.

- Measure the voltage between the headlamp switch C205-4, circuit CLF19 (VT), harness side and ground.






Is the voltage greater than 5 volts?

Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch . TEST the system for normal operation.
No
GO to H3.

H3 CHECK AUTOLAMPS REQUEST INPUT CIRCUIT FOR A SHORT TO GROUND

- Disconnect: SCCM (Steering Column Control Module) C2414A.

- Measure the resistance between the headlamp switch C205-4, circuit CLF19 (VT), harness side and ground.






Is the resistance greater than 10,000 ohms?

Yes
GO to H4.
No
REPAIR circuit CLF19 (VT) for a short to ground. TEST the system for normal operation.

H4 CHECK THE AUTOLAMPS REQUEST INPUT CIRCUIT FOR AN OPEN

- Measure the resistance between the headlamp switch C205-4, circuit CLF19 (VT), harness side and the SCCM (Steering Column Control Module) C2414A-17, circuit CLF19 (VT), harness side.






Is the resistance less than 5 ohms?

Yes
GO to H14.
No
REPAIR circuit CLF19 (VT) for an open. TEST the system for normal operation.

H5 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 PID.

- 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 PID (EXT_LMP_SW).

Do the headlamp switch positions agree with the PID?

Yes
GO to H6.
No
GO to Pinpoint Test C Pinpoint Test C: The Low Beam(s) Are Always On.

H6 USE THE RECORDED DTCs FROM THE BCM (Body Control Module) SELF-TEST

- Check the recorded results from the BCM (Body Control Module) self-test.

Is DTC B1A85:13 or DTC B1A85:11 present?

Yes
For DTC B1A85:13, GO to H8.

For DTC B1A85:11, GO to H12.
No
GO to H7.

H7 CHECK FOR VOLTAGE TO THE LIGHT SENSOR (NO DTC)

- Ignition OFF.

- Disconnect: Light Sensor C287 (Manual Temperature Control) or C286 (Automatic Temperature Control).

- Ignition ON.

- Place the headlamp switch in the AUTOLAMPS ON position.

- On vehicles with automatic temperature control, measure the voltage between the light sensor C286-2, circuit VLF14 (BU), harness side and ground.






- On vehicles with manual temperature control, measure the voltage between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and ground.






Is the voltage approximately 5 volts?

Yes
INSTALL a new light sensor. REFER to Light Sensor . TEST the system for normal operation.
No
GO to H15.

H8 CHECK FOR VOLTAGE TO THE LIGHT SENSOR (DTC B1A85:13)

- Ignition OFF.

- Disconnect: Light Sensor C287 (Manual Temperature Control) or C286 (Automatic Temperature Control).

- Ignition ON.

- Place the headlamp switch in the AUTOLAMPS ON position.

- On vehicles with automatic temperature control, measure the voltage between the light sensor C286-2, circuit VLF14 (BU), harness side and ground.






- On vehicles with manual temperature control, measure the voltage between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and ground.






Is the voltage approximately 5 volts?

Yes
GO to H11.
No
GO to H9.

H9 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: BCM (Body Control Module) C2280B.

- Ignition ON.

- On vehicles with automatic temperature control, measure the voltage between the light sensor C286-2, circuit VLF14 (BU), harness side and ground.






- On vehicles with manual temperature control, measure the voltage between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and ground.






Is any voltage present?

Yes
REPAIR circuit VLF14 (BU/BN) or VLF14 (BU) for a short to voltage. TEST the system for normal operation.
No
GO to H10.

H10 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR AN OPEN

- Ignition OFF.

- On vehicles with automatic temperature control, measure the resistance between the light sensor C286-2, circuit VLF14 (BU), harness side and the BCM (Body Control Module) C2280B-30, circuit VLF14 (BU), harness side.






- On vehicles with manual temperature control, measure the resistance between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and the BCM (Body Control Module) C2280B-30, circuit VLF14 (BU/BN), harness side.






Is the resistance less than 5 ohms?

Yes
GO to H15.
No
REPAIR circuit VLF14 (BU/BN) or VLF14 (BU) for an open. TEST the system for normal operation.

H11 CHECK THE LIGHT SENSOR GROUND CIRCUIT FOR AN OPEN

- For vehicles with automatic temperature control, measure the voltage between the light sensor C286-2, circuit VLF14 (BU), harness side and the light sensor C286-4, circuit RH111 (GY/BU), harness side.






- For vehicles with manual temperature control, measure the voltage between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and the light sensor C287-B, circuit RH111 (GY/BU), harness side.






Is the voltage approximately 5 volts?

Yes
INSTALL a new light sensor. REFER to Light Sensor . TEST the system for normal operation.
No
REPAIR circuit RH111 (GY/BU) for an open. TEST the system for normal operation.

H12 CHECK FOR VOLTAGE TO THE LIGHT SENSOR (DTC B1A85:11)

- Ignition OFF.

- Disconnect: Light Sensor C287 (Manual Temperature Control) or C286 (Automatic Temperature Control).

- Ignition ON.

- Place the headlamp switch in the AUTOLAMPS ON position.

- On vehicles with automatic temperature control, measure the voltage between the light sensor C286-2, circuit VLF14 (BU), harness side and ground.






- On vehicles with manual temperature control, measure the voltage between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and ground.






Is the voltage approximately 5 volts?

Yes
INSTALL a new light sensor. REFER to Light Sensor . TEST the system for normal operation.
No
GO to H13.

H13 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Disconnect: BCM (Body Control Module) C2280B.

- On vehicles with automatic temperature control, measure the resistance between the light sensor C286-2, circuit VLF14 (BU), harness side and ground.






- On vehicles with manual temperature control, measure the resistance between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and ground.






Is the resistance greater than 10,000 ohms?

Yes
GO to H15.
No
REPAIR circuit VLF14 (BU/BN) or VLF14 (BU) for a short to ground. TEST the system for normal operation.

H14 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.

H15 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.

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