Pinpoint Test Y: Both Fog Lamps Are Inoperative

Fog Lamps

Pinpoint Test Y: Both Fog Lamps Are Inoperative

Normal Operation

The Front Lighting Control Module (FLM) monitors the fog lamp switch. When the fog lamp switch is pressed, the FLM (Front Lighting Control Module) sends a message over the High Speed Controller Area Network (HS-CAN) to the Body Control Module (BCM) to indicate the fog lamp request. When the BCM (Body Control Module) receives input from the FLM (Front Lighting 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 (integrated into the FLM (Front Lighting Control Module))

- BCM (Body Control Module)

PINPOINT TEST Y : 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.

Y1 CHECK THE FOG LAMP SWITCH PID

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: FLM (Front Lighting Control Module) DataLogger.

- Monitor the FLM (Front Lighting Control Module) fog lamp switch PID (FOG_F_SW) while pressing and releasing the fog lamp switch.

Does the PID indicate the fog lamp switch is active when pressed and inactive when released?

Yes
VERIFY the BCM (Body Control Module) fuse 47 (15A) is OK. If OK, GO to Y2. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number.

No
INSTALL a new FLM (Front Lighting Control Module). REFER to Front Lighting Control Module (FLM) Service and Repair. TEST the system for normal operation.

Y2 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 Y3.

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

Y3 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.