Pinpoint Test D: The Low Beams Are Always On
Headlamps
Pinpoint Tests
Pinpoint Test D: The Low Beams Are Always On
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) sends voltage signals to the headlamp switch through the headlamp switch input circuits (off, parking lamps, headlamps). At any given time, the headlamp switch routes one of the input circuits to ground.
When the SJB detects the headlamp switch in the HEADLAMPS ON position with the multifunction switch in the LOW BEAM position, the SJB provides voltage to the LH low beam headlamp and the RH low beam headlamp.
If the SJB detects multiple or no headlamp switch input circuits active (short to ground), the SJB turns the parking lamps and headlamps on.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Headlamp switch
- SJB
PINPOINT TEST D: THE LOW BEAMS ARE ALWAYS ON
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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D1 CHECK FOR AUTOLAMP DTCs
- Review the DTCs recorded from the SJB self-test.
- Was DTC B1696, B1791, B1793 or B2008 retrieved?
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 DataLogger.
- While placing the headlamp switch in the AUTOLAMPS ON and then OFF position, monitor the SJB headlamp switch PID (HDLMP_AUT_CKT).
- Does the PID indicate ON with the headlamp switch in the AUTOLAMPS ON position and OFF when the headlamp switch is in the OFF position?
Yes
GO to D3.
No
GO to Pinpoint Test H Pinpoint Test H: The Autolamps Are On Continuously.
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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.
NOTE: Only one PID should indicate ON at each headlamp switch position.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- While moving the headlamp switch through all positions, monitor the SJB headlamp switch input PIDs (HDLMP_OFF_CKT, HDLMP_PRK_CKT and 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 FOR VOLTAGE TO THE HEADLAMP SWITCH INPUT CIRCUITS
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Measure the voltage between the headlamp switch, harness side and ground as follows:
- Are the voltages greater than 10 volts?
Yes
GO to D5.
No
GO to D6.
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D5 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH USING THE CONNECTOR GROUND
- Measure the voltage between the headlamp switch C205-4, circuit CLF23 (WH/VT), harness side and headlamp switch C205-1, circuit GD115 (BK/GY), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD115 (BK/GY) 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 voltage between the headlamp switch, harness side and ground as follows:
- Are the resistances greater than 10,000 ohms?
Yes
GO to D7.
No
REPAIR the circuit in question for an open. 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 for an open. 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. 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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