Pinpoint Test C: One Low Beam Headlamp Is Inoperative
Headlamps
Pinpoint Tests
Pinpoint Test C: One Low Beam Headlamp Is Inoperative
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. Diagrams By Number
Normal Operation
When the Smart Junction Box (SJB) detects the headlamp switch in the HEADLAMPS ON position, the SJB provides voltage to the LH and RH ballasts, located within the High Intensity Discharge (HID) headlamps.
The ballasts utilize a second (hot at all times) voltage feed from the Battery Junction Box (BJB).
When the ballasts are provided voltage from the SJB, high voltage is sent from the ballasts to the HID bulbs.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Ballast
- HID bulb
- Headlamp assembly
- SJB
PINPOINT TEST C: ONE LOW BEAM HEADLAMP IS INOPERATIVE
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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C1 CHECK FOR SJB-SUPPLIED VOLTAGE TO THE HEADLAMP
- Ignition OFF.
- Disconnect: Inoperative Headlamp.
- Place the headlamp switch in the HEADLAMPS ON position.
- Measure the voltage between the LH headlamp C1021-8, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-8, circuit CLF05 (BU/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C6.
No
VERIFY the SJB fuse 7 (10A) (LH low beam) or fuse 8 (10A) (RH low beam) is OK. If OK, GO to C2.
If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: Diagrams By Number
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the low beam output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB. REFER to Body Control Systems. TEST the system for normal operation.
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C2 REPEAT THE SJB SELF-TEST AND CHECK FOR VOLTAGE TO THE HEADLAMP
- Place the headlamp switch in the OFF position.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the DTCs and repeat the on-demand self-test (required to enable the low beam output driver if DTC B106E is present).
- Place the headlamp switch in the HEADLAMPS ON position.
- Measure the voltage between the LH headlamp C1021-8, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-8, circuit CLF05 (BU/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C5.
No
GO to C3.
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C3 CHECK THE LOW BEAM OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: SJB C2280e.
- Measure the resistance between the LH headlamp C1021-8, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-8, circuit CLF05 (BU/GN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to C4.
No
REPAIR circuit CLF04 (BN/BU) (LH low beam) in question for a short to ground. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the low beam output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB. REFER to Body Control Systems. TEST the system for normal operation.
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C4 CHECK LOW BEAM OUTPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the LH headlamp C1021-8, circuit CLF04 (BN/BU), harness side and the SJB C2280e-13, circuit CLF04 (BN/BU), harness side; or between the RH headlamp C1041-8, circuit CLF05 (BU/GN), harness side and the SJB C2280e-4, circuit CLF05 (BU/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to C10.
No
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) for an open. CLEAR the DTCs. REPEAT the self-test.
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C5 CHECK THE HEADLAMP HARNESS (SHORT TO GROUND)
- Remove the ballast. Refer to Ballast Service and Repair.
- Inspect the headlamp harness for shorts.
- Is the headlamp harness OK?
Yes
INSTALL a new ballast. REFER to Ballast Service and Repair.
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the low beam output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB. REFER to Body Control Systems. TEST the system for normal operation.
No
REPAIR or INSTALL a new headlamp assembly. REFER to Headlamp Assembly Service and Repair.
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the low beam output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB. REFER to Body Control Systems. TEST the system for normal operation.
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C6 CHECK THE BALLAST VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Measure the voltage between the LH headlamp C1021-9, circuit SBB16 (VT/RD), harness side and ground; or between the RH headlamp C1041-9, circuit SBB25 (RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C7.
No
VERIFY the BJB fuse 16 (20A) (LH headlamp) or fuse 25 (20A) (RH headlamp) is OK. If OK, REPAIR the circuit in question for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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C7 CHECK FOR VOLTAGE TO THE HEADLAMP USING THE CONNECTOR GROUND
- Measure the voltage between the LH headlamp C1021-9, circuit SBB16 (VT/RD), harness side and the LH headlamp C1021-11, circuit GD120 (BK/GN), harness side; or between the RH headlamp C1041-9, circuit SBB25 (RD), harness side and the RH headlamp C1041-11, circuit GD123 (BK/GY), harness side.
- Is the voltage greater than 10 volts?
Yes
GO to C8.
No
REPAIR the headlamp ground circuit in question for an open. CLEAR the DTCs. REPEAT the self-test.
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C8 CHECK THE HEADLAMP HARNESS FOR OPENS AND SHORTS
- Inspect the headlamp harness for opens and shorts.
- Is the headlamp harness OK?
Yes
GO to C9.
No
REPAIR or INSTALL a new headlamp assembly. REFER to Headlamp Assembly Service and Repair. TEST the system for normal operation.
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C9 CHECK THE BALLAST
- Substitute a known good ballast and recheck the headlamp operation.
- Does the headlamp operate correctly?
Yes
REMOVE the known good ballast. INSTALL a new ballast. REFER to Ballast Service and Repair. TEST the system for normal operation.
No
REMOVE the known good ballast. INSTALL a new HID bulb. REFER to Headlamp Bulb Service and Repair. TEST the system for normal operation.
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C10 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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