Pinpoint Test V: The Fog Lamps Are On Continuously

Fog Lamps

Pinpoint Test V: The Fog Lamps Are On Continuously

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 (Smart Junction Box) detects the fog lamps on request, the SJB (Smart Junction Box) energizes the fog lamp relay (integrated into the SJB (Smart Junction Box)).

When the fog lamp relay is energized on vehicles without the automatic high beam feature, voltage is routed to the fog lamps.

When the fog lamp relay is energized on vehicles with the automatic high beam feature, voltage is routed to the fog lamps deactivation relay (located in the Battery Junction Box (BJB)). When the high beams are not on, voltage passes through the relay to the fog lamps.

- DTC B2254 (Front Fog Lamp Switch Failure)- an on-demand DTC that sets when the SJB (Smart Junction Box) detects a short to ground from the fog lamp on input circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Headlamp switch

- SJB (Smart Junction Box)

PINPOINT TEST V : THE FOG LAMPS ARE ON CONTINUOUSLY

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

V1 CHECK FOR RECORDED SJB (Smart Junction Box) DTCs

- Check the recorded results from the SJB (Smart Junction Box) self-test.

Is DTC B2254 present?

Yes
GO to V2.

No
GO to V4.

V2 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH

- Ignition OFF.

- Disconnect: Headlamp Switch C205.

- Ignition ON.

- Measure the voltage between the headlamp switch C205-6, circuit CLF18 (BU/WH), harness side and ground.





Is the voltage grater than 10 volts?

Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch . CLEAR the DTCs. REPEAT the self-test.

No
GO to V3.

V3 CHECK THE FOG LAMPS REQUEST INPUT CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Disconnect: SJB (Smart Junction Box) C2280B.

- Measure the resistance between the headlamp switch C205-6, circuit CLF18 (BU/WH), harness side and ground.





Is the resistance greater than 10,000 ohms?

Yes
GO to V6.

No
REPAIR circuit CLF18 (BU/WH) for a short to ground. CLEAR the DTCs. REPEAT the self-test.

V4 CHECK THE SJB (Smart Junction Box) OUTPUT

- Ignition OFF.

- Disconnect: SJB (Smart Junction Box) C2280E.

- Ignition ON.

Do the fog lamps continue to illuminate?

Yes
On vehicles not equipped with the automatic high beam feature, REPAIR circuit CLF12 (BN/YE) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.

On vehicles equipped with the automatic high beam feature, GO to V5.

No
GO to V6.

V5 CHECK THE FOG LAMPS VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: Fog Lamps Deactivation Relay.

- Ignition ON.

Do the fog lamps continue to illuminate?

Yes
REPAIR circuit CLF12 (BN/YE) for a short to voltage. TEST the system for normal operation.

No
REPAIR circuit CLF28 (BN/WH) for a short to voltage. TEST the system for normal operation.

V6 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Ignition OFF.

- 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 any DTCs. REPEAT the self-test.