Pinpoint Test D: The Low Beam(s) Are On Continuously
Headlamps
Pinpoint Tests
Pinpoint Test D: The Low Beam(s) 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 CLF19 (VT/GN) (AUTOLAMPS), CLF23 (WH/VT) (OFF), CLS34 (GY) (PARKING LAMPS) and CLF18 (BU/WH) (HEADLAMPS). At any given time, the headlamp switch routes one of the input circuits to ground through joint connector 6 through circuit GD116 (BK/VT).
When the SJB detects the headlamp switch in the HEADLAMPS ON position and the multifunction switch in the LOW BEAM position, the SJB provides voltage through circuits CLF04 (BN/BU) and CLF05 (BU/GN) to the LH and RH low beam headlamps.
B2A2E-B2498:
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Headlamp switch
- SJB
PINPOINT TEST D: THE LOW BEAM(S) 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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D1 CHECK FOR AUTOLAMP DTCs
- Review the DTCs retrieved from the SJB self-test.
- Is DTC B1696, B1791, B1793 or B2008 present?
Yes
Go To Pinpoint Test H. Pinpoint Test H: The Autolamps Are On Continuously
No
If equipped with autolamps, GO to D2.
If not equipped with autolamps, GO to D3.
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D2 CHECK THE SJB AUTOLAMP ON REQUEST PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Data Logger.
- NOTE: Make sure the headlamp switch is in the OFF position when monitoring the PID.
- Monitor the SJB headlamp switch PID (HDLMP_AUT_CKT).
- Does the PID indicate ON?
Yes
Go To Pinpoint Test H. Pinpoint Test H: The Autolamps Are On Continuously
No
GO to D3.
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D3 CHECK THE SJB HEADLAMP SWITCH PIDs
NOTE: Make sure the headlamp switch is lined up in the correct position when monitoring the PIDs.
- Enter the following diagnostic mode on the scan tool: SJB Data Logger.
- NOTE: Only one PID should indicate ON at each headlamp switch position.
- While moving the headlamp switch through all positions, monitor the SJB headlamp switch input PIDs (HDLMP_OFF_CKT, HDLMP_PRK_CKT, HDLMP_ON_CKT).
- Do the headlamp switch positions agree with the PIDs (with only one PID indicating ON in each position)?
Yes
GO to D8.
No
GO to D4.
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D4 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 D5.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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D5 CHECK THE HEADLAMP SWITCH GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the headlamp switch C205-1, circuit GD116 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to D6.
No
REPAIR circuit GD116 (BK/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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D6 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR A SHORT TO GROUND
- Disconnect: SJB C2280b.
- Measure the resistance between the headlamp switch, harness side and ground as follows:
- Is the resistance greater than 10,000 ohms?
Yes
GO to D7.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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D7 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR AN OPEN
- Measure the resistance between the headlamp switch, harness side and the SJB, harness side as follows:
- Are the resistances less than 5 ohms?
Yes
GO to D9.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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D8 CHECK THE SJB OUTPUT
- Disconnect: SJB C2280e.
- Does the LH or RH headlamp continue to illuminate?
Yes
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) for a short to voltage as necessary. CLEAR the DTCs. REPEAT the self-test.
No
GO to D9.
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D9 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. 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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