Pinpoint Test G: The Autolamps Are On Continuously
Autolamps
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 circuit 220 (VT/OG). When the headlamp switch is in the AUTOLAMPS ON position, the signal is routed to ground.
When a request for the autolamps is detected by the LCM, the LCM monitors the state of circuit 218 (WH/VT). The light sensor is provided ground through circuit 676 (PK/OG). When high ambient light conditions exist, the light sensor pulls the voltage signal low. When low ambient light conditions exist, the voltage signal to the light sensor is read high by the LCM. Based on input from the light sensor, the LCM determines when to supply voltage to the exterior lamps.
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) - an on-demand DTC that sets when the LCM detects a short to ground from the wipers on input circuit.
- DTC B1696 (Autolamp On Circuit Short to Ground) - an on-demand DTC that 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.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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G1 CHECK THE LCM HEADLAMP SWITCH PIDs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: LCM DataLogger.
- Monitor the LCM headlamp switch PIDs (HLMPOFF and AUTOLMP) while moving the headlamp switch to the AUTOLAMPS ON and OFF positions.
- Do the headlamp switch positions agree with the PIDs?
Yes
GO to G5.
No
GO to G2.
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G2 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 G3.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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G3 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the headlamp switch C205a-7, circuit 57 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to G4.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G4 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 G13.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G5 CHECK THE LCM WINDSHIELD WIPER MOTOR PID
- Enter the following diagnostic mode on the scan tool: LCM DataLogger.
- Monitor the LCM windshield wiper motor PID (WPRMTRST1).
- Does the PID indicate the windshield wiper motor is active?
Yes
GO to G6.
No
GO to G8.
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G6 CHECK THE WINDSHIELD WIPER MOTOR
- Ignition OFF.
- Disconnect: Windshield Wiper Motor C125.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: LCM DataLogger.
- Monitor the LCM windshield wiper motor PID (WPRMTRST1).
- Does the PID indicate the windshield wiper motor is active?
Yes
GO to G7.
No
INSTALL a new windshield wiper motor. CLEAR the DTCs. REPEAT the self-test.
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G7 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 G13.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G8 CHECK FOR DTC B1472
- Review the DTCs retrieved from the LCM self-test.
- Was DTC B1472 retrieved?
Yes
Go To Pinpoint Test D. Pinpoint Test D: The Headlamps Are On Continuously
No
GO to G9.
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G9 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 G10.
No
GO to G11.
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G10 CHECK CIRCUIT 676 (PK/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the light sensor C287-5, circuit 676 (PK/OG), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new light sensor. REFER to Light Sensor Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G11 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 G12.
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G12 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 G13.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G13 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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