Pinpoint Test S: The Fog Lamps Are On Continuously
Fog Lamps
Pinpoint Tests
Pinpoint Test S: The Fog Lamps Are On Continuously
Refer to Wiring Diagram Set 86, Fog Lamps for schematic and connector information. Diagrams By Number
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 sends a message over the High Speed Controller Area Network (HS-CAN) to the Body Control Module (BCM) to indicate the fog lamp switch position. When the BCM receives input from the SCCM indicating a request for the fog lamps, the BCM provides ground to the fog lamp relay (integrated into the BCM). When the fog lamp relay is energized, voltage is routed to the fog lamps.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Headlamp switch
- SCCM
- BCM
PINPOINT TEST S: 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.
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S1 CHECK THE FOG LAMP SWITCH PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SCCM DataLogger.
- Monitor the SCCM fog lamp switch PID.
- Does the PID indicate the fog lamp switch is on?
Yes
GO to S2.
No
GO to S4.
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S2 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205 .
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SCCM DataLogger.
- Monitor the SCCM fog lamp switch PID.
- Does the PID indicate the fog lamp switch is on?
Yes
GO to S3.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. TEST the system for normal operation.
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S3 CHECK THE FOG LAMP REQUEST INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SCCM C2414a .
- Measure the resistance between the headlamp switch C205-5, circuit CLF21 (GY/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S6.
No
REPAIR circuit CLF21 (GY/VT) for a short to ground. TEST the system for normal operation.
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S4 CHECK THE BCM FOG LAMP INDICATOR OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM C2280a .
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
GO to S5.
No
REPAIR circuit CLF12 (BN/YE) (between the BCM and the headlamp switch) for a short to voltage. TEST the system for normal operation.
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S5 CHECK THE BCM FOG LAMP OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM C2280e .
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
REPAIR circuit CLF12 (BN/YE) (between the BCM and the fog lamps) for a short to voltage. TEST the system for normal operation.
No
GO to S7.
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S6 CHECK FOR CORRECT SCCM OPERATION
- Disconnect all the SCCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SCCM 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. REFER to Steering Column Switches 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.
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S7 CHECK FOR CORRECT BCM OPERATION
- Ignition OFF.
- Disconnect all the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM 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. 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.
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