Pinpoint Test Q: Both Fog Lamps Are Inoperative

Fog Lamps

Pinpoint Test Q: Both Fog Lamps Are Inoperative

Normal Operation

The Steering Column Control Module (SCCM) monitors the fog lamp switch position by sending a voltage signal to the headlamp switch. When the fog lamp switch is engaged, the voltage signal is routed to ground indicating a request for the fog lamps.

The SCCM (Steering Column Control Module) sends a message to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN), indicating the fog lamp switch position. When the BCM (Body Control Module) receives input from the SCCM (Steering Column Control Module) indicating a request for the fog lamps, the BCM (Body Control Module) provides ground to the fog lamp relay (integrated into the BCM (Body Control Module) ). 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

- SCCM (Steering Column Control Module)

- BCM (Body Control Module)

PINPOINT TEST Q : 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.

Q1 CHECK THE FOG LAMP SWITCH PID

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: SCCM (Steering Column Control Module) DataLogger.

- Monitor the SCCM (Steering Column Control Module) fog lamp switch PID (FOG_F_SW) while engaging the fog lamp switch.

Does the PID indicate the fog lamp switch is on?

Yes
VERIFY the BCM (Body Control Module) fuse 47 (15A) is OK. If OK, GO to Q4. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number.
No
GO to Q2.

Q2 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.






Is the voltage greater than 5 volts?

Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch . TEST the system for normal operation.
No
GO to Q3.

Q3 CHECK THE FOG LAMP REQUEST INPUT CIRCUIT FOR AN OPEN

- Disconnect: SCCM (Steering Column Control Module) C2414A.

- Measure the resistance between the headlamp switch C205-5, circuit CLF21 (GY/VT), harness side and the SCCM (Steering Column Control Module) C2414A-1, circuit CLF21 (GY/VT), harness side.






Is the resistance less than 5 ohms?

Yes
GO to Q5.
No
REPAIR circuit CLF21 (GY/VT) for an open. TEST the system for normal operation.

Q4 BYPASS THE BCM (Body Control Module)
NOTE: If the fuse in the jumper wire fails, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number.

- Ignition OFF.

- Disconnect: BCM (Body Control Module) C2280E.

- Connect a fused jumper wire between the BCM (Body Control Module) C2280E-5, circuit CLF12 (BN/YE), harness side and battery positive.






Do the fog lamps illuminate?

Yes
REMOVE the jumper wire. GO to Q6.
No
REMOVE the jumper wire. REPAIR circuit CLF12 (BN/YE) for an open. TEST the system for normal operation.

Q5 CHECK FOR CORRECT SCCM (Steering Column Control Module) OPERATION

- Disconnect all the SCCM (Steering Column Control Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SCCM (Steering Column Control Module) 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 SCCM (Steering Column Control Module). 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.

Q6 CHECK FOR CORRECT BCM (Body Control Module) OPERATION

- Disconnect all the BCM (Body Control Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the BCM (Body Control Module) 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 BCM (Body Control Module). 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.