Pinpoint Test B: One Low Beam Headlamp Is Inoperative
Headlamps
Pinpoint Test B: One Low Beam Headlamp Is Inoperative
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information [1][2]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 (Smart Junction Box) provides voltage to the LH and RH low beam headlamps.
Vehicles equipped with High Intensity Discharge (HID) headlamps utilize a second (hot at all times) voltage feed to the ballasts from the Battery Junction Box (BJB).
When the ballasts receive the headlamp on voltage from the SJB (Smart Junction Box) , the ballasts provide high voltage to the HID (High Intensity Discharge) bulbs.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Ballast
- Bulb
- Headlamp assembly (HID (High Intensity Discharge) only)
- SJB (Smart Junction Box)
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, certain aftermarket halogen bulbs may cause the SJB (Smart Junction Box) 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 (Smart Junction Box)). Correct any unresolved DTCs. Clear all DTCs. Test the system for normal operation.
B1 CHECK FOR VOLTAGE TO THE HEADLAMP
- Ignition OFF.
- Disconnect: Inoperative Headlamp.
- Place the headlamp switch in the HEADLAMPS ON position.
- For vehicles with halogen headlamps, 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.
- For vehicles with HID (High Intensity Discharge) headlamps, measure the voltage between the LH headlamp C1284-1, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1285-1, circuit CLF05 (BU/GN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
For vehicles with HID (High Intensity Discharge) headlamps, GO to B2.
For vehicles with halogen headlamps, GO to B3.
No
VERIFY the SJB (Smart Junction Box) fuse 7 (10A) (LH low beam) or fuse 8 (10A) (RH low beam) is OK. GO to B6.
B2 CHECK BALLAST SUPPLY VOLTAGE TO THE HEADLAMP
- Measure the voltage between the LH headlamp C1284-3, circuit SBB26 (YE/RD), harness side and ground; or between the RH headlamp C1285-3, circuit SBB27 (BU/RD), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B3.
No
VERIFY the BJB (Battery Junction Box) fuse 26 (20A) (LH headlamp) or fuse 27 (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 [1][2]Diagrams By Number. GO to B9.
B3 CHECK FOR VOLTAGE TO THE HEADLAMP USING THE CONNECTOR GROUND
- For vehicles with halogen headlamps, measure the voltage between the LH headlamp C1021-1, circuit CLF04 (BN/BU), harness side and the LH headlamp C1021-2, circuit GD129 (BK/YE), harness side; or between the RH headlamp C1041-1, circuit CLF05 (BU/GN), harness side and the RH headlamp C1041-2, circuit GD123 (BK/GY), harness side.
- For vehicles with HID (High Intensity Discharge) headlamps, measure the voltage between the LH headlamp C1284-1, circuit CLF04 (BN/BU), harness side and the LH headlamp C1284-2, circuit GD129 (BK/YE), harness side; or between the RH headlamp C1285-1, circuit CLF05 (BU/GN), harness side and the RH headlamp C1285-2, circuit GD123 (BK/GY), harness side.
Is the voltage greater than 10 volts?
Yes
For vehicles with halogen headlamps, INSTALL a new headlamp bulb. REFER to Headlamp Bulb . TEST the system for normal operation.
For vehicles with HID (High Intensity Discharge) headlamps, GO to B4.
No
REPAIR circuit GD129 (BK/YE) (LH headlamp) or circuit GD123 (BK/GY) (RH headlamp) for an open. TEST the system for normal operation.
B4 CHECK THE HEADLAMP HARNESS FOR AN OPEN OR SHORT
- Inspect the headlamp harness for an open or short.
Is the headlamp harness OK?
Yes
GO to B5.
No
REPAIR or INSTALL a new headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation.
B5 CHECK THE BALLAST
- Substitute a known good ballast and recheck the headlamp operation.
Does the headlamp operate correctly?
Yes
INSTALL a new ballast. REFER to Ballast . TEST the system for normal operation.
No
INSTALL a new HID (High Intensity Discharge) bulb. REFER to Headlamp Bulb . TEST the system for normal operation.
B6 USE THE RECORDED DTCs FROM THE SJB (Smart Junction Box) SELF-TEST
- Place the headlamp switch in the OFF position.
- Check the recorded results from the SJB (Smart Junction Box) self-test.
Is DTC B2A2E or DTC B2A30 present?
Yes
GO to B7.
No
GO to B8.
B7 CHECK THE SJB (Smart Junction Box) LOW BEAM OUTPUT CIRCUIT FOR AN OPEN
- Disconnect: SJB (Smart Junction Box) C2280E.
- For vehicles with halogen headlamps, measure the resistance between the LH headlamp C1021-1, circuit CLF04 (BN/BU), harness side and the SJB (Smart Junction Box) C2280E-13, circuit CLF04 (BN/BU), harness side; or between the RH headlamp C1041-1, circuit CLF05 (BU/GN), harness side and the SJB (Smart Junction Box) C2280E-4, circuit CLF05 (BU/GN), harness side.
- For vehicles with HID (High Intensity Discharge) headlamps, measure the resistance between the LH headlamp C1284-1, circuit CLF04 (BN/BU), harness side and the SJB (Smart Junction Box) C2280E-13, circuit CLF04 (BN/BU), harness side; or between the RH headlamp C1285-1, circuit CLF05 (BU/GN), harness side and the SJB (Smart Junction Box) C2280E-4, circuit CLF05 (BU/GN), harness side.
Is the resistance less than 5 ohms?
Yes
GO to B11.
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.
B8 ISOLATE THE HEADLAMP AS THE CAUSE OF THE SHORT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB (Smart Junction Box) 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.
- For vehicles with halogen headlamps, 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.
- For vehicles with HID (High Intensity Discharge) headlamps, measure the voltage between the LH headlamp C1284-1, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1285-1, circuit CLF05 (BU/GN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
For vehicles with halogen headlamps, INSTALL a new headlamp bulb. REFER to Headlamp Bulb . TEST the system for normal operation.
For vehicles with HID (High Intensity Discharge) headlamps, GO to B9.
No
GO to B10.
B9 CHECK THE HEADLAMP HARNESS FOR A SHORT TO GROUND
- Inspect the headlamp harness for a short to ground.
Is the headlamp harness OK?
Yes
INSTALL a new ballast. REFER to Ballast . TEST the system for normal operation.
No
REPAIR or INSTALL a new headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation.
B10 CHECK THE SJB (Smart Junction Box) LOW BEAM OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280E.
- For vehicles with halogen headlamps, 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.
- For vehicles with HID (High Intensity Discharge) headlamps, measure the resistance between the LH headlamp C1284-1, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1285-1, circuit CLF05 (BU/GN), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to B11.
No
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) 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 (Smart Junction Box). TEST the system for normal operation.
B11 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION
- Disconnect all the SJB (Smart Junction Box) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB (Smart Junction Box) 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 (Smart Junction Box). 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.