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 - Fusion and MKZ With Halogen Headlamps
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.
MKZ with High Intensity Discharge (HID) Headlamps
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 headlamp relays. When the headlamp relays are energized, voltage is switched to the headlamps.
For MKZ with HID (High Intensity Discharge) headlamps, the ballasts then provide the required high voltage to illuminate the HID (High Intensity Discharge) headlamp bulbs.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Headlamp relay
- Ballast
- Bulb
- Headlamp assembly
- 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 of certain aftermarket headlamp bulbs, the SJB (Smart Junction Box) may activate its short circuit protection strategy, resulting in the low beam output circuit(s) becoming inoperative. Verify that the bulbs meet Ford specifications. If the bulbs do not meet Ford specifications, install the correct bulbs. Clear the DTCs and run the on-demand self-test (required to reset the
SJB (Smart Junction Box)). Correct any unresolved 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 Fusion or MKZ with halogen headlamps, measure the voltage between the LH headlamp C1021-6, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-6, circuit CLF05 (BU/GN), harness side and ground.
- For MKZ with HID (High Intensity Discharge) headlamps, measure the voltage between the LH headlamp C1021-6, circuit CLF30 (VT/BN), harness side and ground; or between the RH headlamp C1041-6, circuit CLF31 (YE/GY), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B2.
No
For MKZ with halogen headlamps or Fusion, GO to B5.
For MKZ with HID (High Intensity Discharge) headlamps, GO to B10.
B2 CHECK FOR VOLTAGE TO THE HEADLAMP USING THE CONNECTOR GROUND
- For Fusion or MKZ with halogen headlamps, measure the voltage between the LH headlamp C1021-6, circuit CLF04 (BN/BU), harness side and the LH headlamp C1021-1, circuit GD121 (BK/YE), harness side; or between the RH headlamp C1041-6, circuit CLF05 (BU/GN), harness side and the RH headlamp C1041-1, circuit GD123 (BK/GY), harness side.
- For MKZ with HID (High Intensity Discharge) headlamps, measure the voltage between the LH headlamp C1021-6, circuit CLF30 (VT/BN), harness side and the LH headlamp C1021-1, circuit GD121 (BK/YE), harness side; or between the RH headlamp C1041-6, circuit CLF31 (YE/GY), harness side and the RH headlamp C1041-1, circuit GD123 (BK/GY), harness side.
Is the voltage greater than 10 volts?
Yes
For MKZ with HID (High Intensity Discharge) headlamps, GO to B3.
For all others, REPAIR or INSTALL a new headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation.
No
REPAIR circuit GD121 (BK/YE) (LH headlamp) or circuit GD123 (BK/GY) for an open. TEST the system for normal operation.
B3 SUBSTITUTE THE HID (High Intensity Discharge) BULB
- Place the headlamp switch in the OFF position.
- Substitute a known good HID (High Intensity Discharge) bulb.
- Place the headlamp switch in the HEADLAMPS ON position.
Does the headlamp illuminate?
Yes
INSTALL a new HID (High Intensity Discharge) headlamp bulb. REFER to Headlamp Bulb - LH, MKZ or Headlamp Bulb - RH, MKZ . TEST the system for normal operation.
No
REINSTALL the HID (High Intensity Discharge) bulb. GO to B4.
B4 SUBSTITUTE THE BALLAST
- Place the headlamp switch in the OFF position.
- Substitute a known good ballast.
- Place the headlamp switch in the HEADLAMPS ON position.
Does the headlamp illuminate?
Yes
INSTALL a new ballast. REFER to Ballast . TEST the system for normal operation.
No
INSTALL a new headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation.
B5 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 B6.
No
VERIFY the SJB (Smart Junction Box) fuse 7 (10A) (LH low beam) or fuse 8 (10A) (RH low beam) is OK. If OK, GO to B7.
If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: [1][2]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 (Smart Junction Box). TEST the system for normal operation.
B6 CHECK THE SJB (Smart Junction Box) HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN (FUSION OR MKZ WITH HALOGEN HEADLAMPS)
- Disconnect: SJB (Smart Junction Box) C2280E.
- Measure the resistance between the LH headlamp C1021-6, 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 C1041-6, 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 B21.
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.
B7 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.
- Measure the voltage between the LH headlamp C1021-6, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-6, circuit CLF05 (BU/GN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B9.
No
GO to B8.
B8 CHECK THE SJB (Smart Junction Box) LOW BEAM OUTPUT CIRCUIT FOR A SHORT TO GROUND (FUSION OR MKZ WITH HALOGEN HEADLAMPS)
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280E.
- Measure the resistance between the LH headlamp C1021-6, circuit CLF04 (BN/BU), harness side and ground; or between the RH headlamp C1041-6, circuit CLF05 (BU/GN), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to B21.
No
REPAIR circuit CLF04 (BN/BU) (LH low beam) or circuit CLF05 (BU/GN) (RH low beam) 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.
B9 ISOLATE THE HEADLAMP AS THE CAUSE OF THE SHORT (FUSION OR MKZ WITH HID (High Intensity Discharge) HEADLAMPS)
- Ignition ON.
- Disconnect: Headlamp Bulb.
- Connect: Headlamp Assembly.
- 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.
Is DTC B2A31 (LH headlamp) or DTC B2A2F (RH headlamp) present?
Yes
INSTALL a new headlamp assembly. REFER to Headlamp Assembly . 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.
No
INSTALL a new headlamp bulb. REFER to Headlamp Bulb - LH, Fusion or Headlamp Bulb - RH, Fusion . 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.
B10 CHECK THE HEADLAMP RELAY
- Place the headlamp switch in the OFF position.
- Disconnect: Suspect Headlamp Relay.
- Substitute a known good relay.
- 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.
- Measure the voltage between the LH headlamp C1021-6, circuit CLF30 (VT/BN), harness side and ground; or between the RH headlamp C1041-6, circuit CLF31 (YE/GY), harness side and ground.
Is the voltage greater than 10 volts?
Yes
REMOVE the known good relay. INSTALL a new headlamp relay. TEST the system for normal operation.
No
For MKZ non-Hybrid, REMOVE the known good relay. GO to B11.
For MKZ Hybrid, REMOVE the known good relay. GO to B16.
B11 CHECK FOR VOLTAGE TO THE HEADLAMP RELAY
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 3, circuit SBB26 (YE/RD), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 3, circuit SBB27 (BU/RD), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B12.
No
VERIFY the BJB (Battery Junction Box) fuse 26 (15A) (LH headlamp) or fuse 27 (15A) (RH headlamp) is OK. If OK, REPAIR circuit SBB26 (YE/RD) (LH headlamp) or circuit SBB27 (BU/RD) (RH headlamp) 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
B12 CHECK FOR VOLTAGE TO THE HEADLAMP RELAY USING THE RELAY GROUND
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 3, circuit SBB26 (YE/RD), BJB (Battery Junction Box) face side and the LH headlamp relay pin 2, circuit GD121 (BK/YE), BJB (Battery Junction Box) face side.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 3, circuit SBB27 (BU/RD), BJB (Battery Junction Box) face side and the RH headlamp relay pin 2, circuit GD121 (BK/YE), BJB (Battery Junction Box) face side.
Is the voltage greater than 10 volts?
Yes
GO to B13.
No
REPAIR circuit GD121 (BK/YE) for an open. TEST the system for normal operation
B13 BYPASS THE HEADLAMP RELAY
- Connect: Headlamp Assembly.
- For the LH headlamp, connect a fused jumper wire between the LH headlamp relay pin 3, circuit SBB26 (YE/RD), BJB (Battery Junction Box) face side and the LH headlamp relay pin 5, circuit CLF30 (VT/BN), BJB (Battery Junction Box) face side.
- For the RH headlamp, connect a fused jumper wire between the RH headlamp relay pin 3, circuit SBB27 (BU/RD), BJB (Battery Junction Box) face side and the RH headlamp relay pin 5, circuit CLF31 (YE/GY), BJB (Battery Junction Box) face side.
Does the headlamp illuminate?
Yes
REMOVE the jumper wire. GO to B14.
No
REMOVE the jumper wire. REPAIR circuit CLF30 (VT/BN) (LH headlamp) or circuit CLF31 (YE/GY) (RH headlamp) for an open. TEST the system for normal operation.
B14 CHECK THE SJB (Smart Junction Box) LOW BEAM OUTPUT CIRCUIT FOR A SHORT TO GROUND (MKZ NON-HYBRID HID (High Intensity Discharge) HEADLAMPS)
- Disconnect: SJB (Smart Junction Box) C2280E.
- For the LH headlamp, measure the resistance between the LH headlamp relay pin 1, circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the resistance between the RH headlamp relay pin 1, circuit CLF05 (BU/GN), BJB (Battery Junction Box) face side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to B15.
No
REPAIR circuit CLF04 (BN/BU) (LH low beam) or circuit CLF05 (BU/GN) (RH low beam) 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.
B15 CHECK THE SJB (Smart Junction Box) HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN (MKZ NON-HYBRID HID (High Intensity Discharge) HEADLAMPS)
- For the LH headlamp, measure the resistance between the LH headlamp relay pin 1, circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and the SJB (Smart Junction Box) C2280E-13, circuit CLF04 (BN/BU), harness side.
- For the RH headlamp, measure the resistance between the RH headlamp relay pin 1, circuit CLF05 (BU/GN), BJB (Battery Junction Box) face 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 B21.
No
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) for an open. TEST the system for normal operation.
B16 CHECK FOR VOLTAGE TO THE HEADLAMP RELAY (MKZ HYBRID)
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 3, circuit SBB26 (YE/RD), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 3, circuit SBB27 (BU/RD), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B17.
No
VERIFY the BJB (Battery Junction Box) fuse 26 (15A) (LH headlamp) or fuse 27 (15A) (RH headlamp) is OK. If OK, REPAIR circuit SBB26 (YE/RD) (LH headlamp) or circuit SBB27 (BU/RD) (RH headlamp) 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
B17 CHECK FOR VOLTAGE TO THE HEADLAMP RELAY USING THE RELAY GROUND (MKZ HYBRID)
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 3, circuit SBB26 (YE/RD), BJB (Battery Junction Box) face side and the LH headlamp relay pin 1, circuit GD123 (BK/GY), BJB (Battery Junction Box) face side.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 3, circuit SBB27 (BU/RD), BJB (Battery Junction Box) face side and the RH headlamp relay pin 1 circuit GD123 (BK/GY)BJB (Battery Junction Box) face side.
Is the voltage greater than 10 volts?
Yes
GO to B18.
No
REPAIR circuit GD121 (BK/YE) for an open. TEST the system for normal operation
B18 BYPASS THE HEADLAMP RELAY (MKZ HYBRID)
- Connect: Headlamp Assembly.
- For the LH headlamp, connect a fused jumper wire between the LH headlamp relay pin 3, circuit SBB26 (YE/RD), BJB (Battery Junction Box) face side and the LH headlamp relay pin 5, circuit CLF30 (VT/BN), BJB (Battery Junction Box) face side.
- For the RH headlamp, connect a fused jumper wire between the RH headlamp relay pin 3, circuit SBB27 (BU/RD), BJB (Battery Junction Box) face side and the RH headlamp relay pin 5, circuit CLF31 (YE/GY), BJB (Battery Junction Box) face side.
Does the headlamp illuminate?
Yes
REMOVE the jumper wire. GO to B19.
No
REMOVE the jumper wire. REPAIR circuit CLF30 (VT/BN) (LH headlamp) or circuit CLF31 (YE/GY) (RH headlamp) for an open. TEST the system for normal operation.
B19 CHECK THE SJB (Smart Junction Box) LOW BEAM OUTPUT CIRCUIT FOR A SHORT TO GROUND (MKZ HYBRID)
- Disconnect: SJB (Smart Junction Box) C2280E.
- For the LH headlamp, measure the resistance between the LH headlamp relay pin 2 circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the resistance between the RH headlamp relay pin 2 circuit CLF05 (BU/GN), BJB (Battery Junction Box) face side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to B20.
No
REPAIR circuit CLF04 (BN/BU) (LH low beam) or circuit CLF05 (BU/GN) (RH low beam) 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.
B20 CHECK THE SJB (Smart Junction Box) HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN (MKZ HYBRID)
- For the LH headlamp, measure the resistance between the LH headlamp relay pin 2 circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and the SJB (Smart Junction Box) C2280E-13, circuit CLF04 (BN/BU), harness side.
- For the RH headlamp, measure the resistance between the RH headlamp relay pin 2 circuit CLF05 (BU/GN), BJB (Battery Junction Box) face 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 B16.
No
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) for an open. TEST the system for normal operation.
B21 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.