Pinpoint Test I: The Autolamps Are On Continuously
Autolamps
Pinpoint Tests
Pinpoint Test I: The Autolamps Are On Continuously
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) sends reference signals to the headlamp switch through circuits CLF18 (BU/WH), CLF19 (VT/GN), CLF23 (WH/VT) and CLS34 (GY). The SJB also sends a reference signal to the light sensor through circuit VLF14 (BU/BN). Ground for the light sensor is sent through circuit GD116 (BK/VT). When the headlamp switch is placed in the AUTOLAMPS ON position, the voltage signal is routed to ground through circuit GD116 (BK/VT). When the SJB detects the headlamp switch in the AUTOLAMPS ON position, the SJB sends voltage to the exterior lamps if the ambient light conditions are dark. The light sensor determines the amount of light based on the input received from the ambient sky conditions. When the ambient level has reached a point (determined by the internal programming of the SJB), the SJB sends voltage to the headlamps, parking, and license plate lamps.
- DTC B1692 (Autolamp Delay Circuit Short to Ground) - an on-demand DTC that sets when the SJB detects a short to ground from the autolamps on input circuit.
- DTC B1791 (Autolamp Sensor Input Circuit Open) - a continuous DTC that sets when the SJB 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
- SJB
PINPOINT TEST I: 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: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Body Control Systems.
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I1 RETRIEVE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Retrieve the recorded results from the SJB self-test.
- Is DTC B1472, B1578 or B2498 present?
Yes
Go To Pinpoint Test E. Pinpoint Test E: The Low Beam(S) Are Always on
No
GO to I2.
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I2 CHECK THE SJB HEADLAMP SWITCH PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB headlamp switch PIDs (AUTOLMP) while moving the headlamp switch from the OFF to the AUTOLAMPS ON position.
- Does the headlamp switch position agree with the PID?
Yes
GO to I6.
No
GO to I3.
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I3 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Carry out the headlamp switch component test.
- Is the headlamp switch OK?
Yes
GO to I4.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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I4 CHECK CIRCUIT CLF19 (VT/GN) FOR A SHORT TO GROUND
- Disconnect: SJB C2280d.
- Measure the resistance between the headlamp switch C205-9, circuit CLF19 (VT/GN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to I5.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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I5 CHECK CIRCUIT CLF19 (VT/GN) FOR AN OPEN
- Disconnect: SJB C2280d.
- Measure the resistance between the headlamp switch C205-9, circuit CLF19 (VT/GN), harness side and the SJB C2280d-19, circuit CLF19 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to I10.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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I6 CHECK FOR VOLTAGE TO THE LIGHT SENSOR
- Ignition OFF.
- Disconnect: Light Sensor C286.
- Ignition ON.
- Place the headlamp switch in the AUTOLAMPS ON position.
- Measure the voltage between the light sensor C286-2, circuit VLF14 (BU/BN), harness side and ground.
- Is the voltage approximately 5 volts?
Yes
GO to I7.
No
GO to I8.
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I7 CHECK THE VOLTAGE TO THE LIGHT SENSOR USING THE CONNECTOR GROUND
- Measure the voltage between the light sensor C286-2, circuit VLF14 (BU/BN), harness side and the light sensor C286-4, circuit GD116 (BK/VT), harness side.
- Is the voltage approximately 5 volts?
Yes
INSTALL a new light sensor. REFER to Light Sensor Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD116 (BK/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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I8 CHECK CIRCUIT VLF14 (BU/BN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: SJB C2280d.
- Ignition ON.
- Measure the voltage between the light sensor C286-2, circuit VLF14 (BU/BN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to I9.
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I9 CHECK CIRCUIT VLF14 (BU/BN) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the light sensor C286-2, circuit VLF14 (BU/BN), harness side and the SJB C2280d-13, circuit VLF14 (BU/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to I10.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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I10 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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 SJB. REFER to Body Control Systems. 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. CLEAR the DTCs. REPEAT the self-test.
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