Pinpoint Test B: One Low Beam Headlamp Is Inoperative
Headlamps
Pinpoint Tests
Pinpoint Test B: One Low Beam Headlamp Is Inoperative
Refer to Wiring Diagram Set 85, Headlamps 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 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. Ground is supplied through circuits GD120 (BK/GN) and GD164 (BK/VT) to the LH and RH low beam headlamps.
B2A2E-B2A31:
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- SJB
PINPOINT TEST B: 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.
NOTE: Due to varying wattage ratings and resulting current draw differences, certain aftermarket headlamp bulbs may cause the SJB to shut down the short circuit protection, resulting in the low beams becoming inoperative. Verify that the bulbs meet Ford specifications. If the bulbs do not meet Ford specifications, install the correct bulbs. Run the on-demand self-test (required to clear certain DTCs and reset the SJB). Correct any unresolved DTCs. Clear all DTCs. Test the system for normal operation.
NOTE: Make sure the headlamp bulb is good before continuing diagnostics.
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B1 USE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Check the recorded results from the SJB self-test.
- Was DTC B2A2E or B2A30 recorded?
Yes
GO to B2.
No
GO to B4.
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B2 CHECK FOR 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 C1021-1, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-1, circuit CLF05 (BU/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit GD120 (BK/GN) (LH headlamp) or circuit GD164 (BK/VT) (RH headlamp) for an open. CLEAR the DTCs. REPEAT the self-test.
No
VERIFY the SJB fuse 7 (10A) (LH low beam) or fuse 8 (10A) is OK. If OK, GO to B3. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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B3 CHECK THE SJB HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Place the headlamp switch in the OFF position.
- Disconnect: SJB C2280e.
- Measure the resistance between the LH headlamp C1021-1, circuit CLF04 (BN/BU), harness side and the SJB C2280e-13, circuit CLF04 (BN/BU), harness side; or between the RH headlamp C1041-1, 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 B5.
No
REPAIR the circuit in question for an open. CLEAR the DTCs. REPEAT the self-test.
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B4 CHECK THE SJB HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280e.
- Disconnect: Inoperative Headlamp.
- Measure the resistance between the LH headlamp C1021-1, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-1, circuit CLF05 (BU/GN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to B5.
No
REPAIR the circuit in question for a short to ground. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.
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B5 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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