Pinpoint Test G: The Autolamps Are On Continuously
Autolamps
Pinpoint Tests
Pinpoint Test G: The Autolamps Are On Continuously
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. Diagrams By Number
Normal Operation
The Lighting Control Module (LCM) sends voltage reference signals to the headlamp switch through circuits 220 (VT/OG) (autolamps position) and 1400 (TN/WH) (off position). The headlamp switch routes the signal to ground through circuit 57 (BK) for any given headlamp switch position. If the LCM detects a fault with the headlamp switch input, the LCM defaults the exterior lamps on.
When a request for the autolamps is detected by the LCM, the LCM monitors the state of circuit 218 (WH/VT). When a low ambient light condition is present, the signal circuit is high, and the LCM supplies voltage to the exterior lamps. When a high ambient light condition is present, the light sensor pulls the voltage signal low, and the LCM deactivates the voltage to the exterior lamps. The light sensor is provided ground through circuit 676 (PK/OG).
The LCM also sends a voltage reference signal to the windshield wiper motor through circuit 28 (BK/PK). When the wiper motor is on, the signal is routed to ground.
- DTC B1449 (Wiper Park Sense Circuit Short to Ground) - sets when the LCM detects a short to ground from the wipers on input circuit.
- DTC B1696 (Autolamp On Circuit Short to Ground) - sets when the LCM detects a short to ground from the autolamps lamps on input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Light sensor
- Headlamp switch
- Windshield wiper motor
- LCM
PINPOINT TEST G: 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.
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G1 DETERMINE IF THE EXTERIOR LAMPS ARE ON WITH THE HEADLAMP SWITCH OFF
- Ignition OFF.
- NOTE: Make sure the headlamp switch is in the OFF position.
- Observe the exterior lamps.
- Are the exterior lamps on?
Yes
Go To Pinpoint Test D Testing and Inspection.
No
GO to G2.
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G2 CHECK FOR DTC B1449
- Retrieve the recorded results from the LCM self-test.
- Is DTC B1449 present?
Yes
GO to G3.
No
GO to G5.
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G3 CHECK THE WINDSHIELD WIPER MOTOR
- Disconnect: Windshield Wiper Motor C125.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: LCM Self-Test.
- Clear the DTCs and repeat the LCM on-demand self-test.
- Is DTC B1449 still present?
Yes
GO to G4.
No
INSTALL a new windshield wiper motor. CLEAR the DTCs. REPEAT the self-test.
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G4 CHECK CIRCUIT 28 (BK/PK) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: LCM C2145d.
- Measure the resistance between the windshield wiper motor C125-2, circuit 28 (BK/PK), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to G12.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G5 CHECK THE LCM HEADLAMP SWITCH PIDs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: LCM DataLogger.
- Monitor the LCM headlamp switch PID (AUTOLAMP) while moving the headlamp switch from the OFF to the AUTOLAMPS ON positions.
- Does the headlamp switch position agree with the PID?
Yes
GO to G8.
No
GO to G6.
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G6 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205a.
- Carry out the headlamp switch component test.
- Is the headlamp switch OK?
Yes
GO to G7.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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G7 CHECK CIRCUIT 220 (VT/OG) FOR AN OPEN AND SHORT TO GROUND
- Disconnect: LCM C2145a.
- Measure the resistance between the headlamp switch C205a-4, circuit 220 (VT/OG), harness side and the LCM C2145a-15, circuit 220 (VT/OG), harness side: and between the headlamp switch C205a-4, circuit 220 (VT/OG), harness side and ground.
- Is the resistance less than 5 ohms between the headlamp switch and the LCM, and greater than 10,000 ohms between the headlamp switch and ground?
Yes
GO to G12.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G8 CHECK FOR VOLTAGE TO THE LIGHT SENSOR
- Ignition OFF.
- Disconnect: Light Sensor C287.
- Ignition ON.
- Place the headlamp switch in the AUTOLAMPS ON position.
- Measure the voltage between the light sensor C287-2, circuit 218 (WH/VT), harness side and ground.
- Is the voltage approximately 5 volts?
Yes
GO to G9.
No
GO to G10.
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G9 CHECK FOR VOLTAGE TO THE LIGHT SENSOR USING THE CONNECTOR GROUND
- Measure the voltage between the light sensor C287-2, circuit 218 (WH/VT), harness side and the light sensor C287-5, circuit 676 (PK/OG), harness side and ground.
- 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 676 (PK/OG) for an open. CLEAR the DTCs. REPEAT the self-test.
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G10 CHECK CIRCUIT 218 (WH/VT) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: LCM C2145a.
- Ignition ON.
- Measure the voltage between the light sensor C287-2, circuit 218 (WH/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to G11.
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G11 CHECK CIRCUIT 218 (WH/VT) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the light sensor C287-2, circuit 218 (WH/VT), harness side and the LCM C2145a-1, circuit 218 (WH/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to G12.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G12 CHECK FOR CORRECT LCM OPERATION
- Ignition OFF.
- Disconnect all the LCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the LCM 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 LCM. 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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