Pinpoint Test S: Both Fog Lamps Are Inoperative

Fog Lamps

Pinpoint Test S: Both Fog Lamps Are Inoperative

Refer to Wiring Diagram Set 86 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Fog Lamps for schematic and connector information. Diagrams By Number

Normal Operation

The Smart Junction Box (SJB) sends a voltage signal to the headlamp switch to monitor the fog lamp request. When the fog lamp switch is engaged, the voltage signal is routed to ground.

When the SJB detects the fog lamps on request, the SJB energizes the fog lamp relay (integrated into the SJB). When the fog lamp relay is energized, voltage is routed to the fog lamps.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- Headlamp switch
- SJB


PINPOINT TEST S: BOTH FOG LAMPS ARE INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

-------------------------------------------------
S1 CHECK THE SJB FOG LAMP SWITCH PID

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Data Logger.
- Monitor the SJB fog lamp PID (FOG SW) while engaging the fog lamp switch.
- Does the PID indicate the fog lamp switch is on?

Yes
VERIFY the SJB fuse 21 (15A) is OK. If OK, GO to S4. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number

No
GO to S2.

-------------------------------------------------
S2 CHECK FOR A VOLTAGE SIGNAL TO THE HEADLAMP SWITCH

- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Measure the voltage between the headlamp switch C205-5, circuit CLF21 (GY/VT), harness side and ground.




- Ignition ON.
- Is the voltage greater than 10 volts?

Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. TEST the system for normal operation.

No
GO to S3.

-------------------------------------------------
S3 CHECK THE FOG LAMPS ON REQUEST INPUT CIRCUIT FOR AN OPEN

- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the headlamp switch C205-5, circuit CLF21 (GY/VT), harness side and the SJB C2280b-49, circuit CLF21 (GY/VT), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to S5.

No
REPAIR circuit CLF21 (GY/VT) for an open. TEST the system for normal operation.

-------------------------------------------------
S4 BYPASS THE SJB

- Ignition OFF.
- Disconnect: SJB C2280e.
- Connect a fused jumper wire between the SJB C2280e-1, circuit CDC34 (WH/OG), harness side and the SJB C2280e-3, circuit CLF12 (BN/YE), harness side.




- Ignition ON.
- Do the fog lamps illuminate?

Yes
REMOVE the jumper wire. GO to S5.

No
REMOVE the jumper wire. REPAIR circuit CLF12 (BN/YE) for an open. TEST the system for normal operation.

-------------------------------------------------
S5 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 Multifunction Electronic Modules Service and Repair. 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.

-------------------------------------------------