Pinpoint Test U: The Fog Lamps Are On Continuously
Fog Lamps
Pinpoint Tests
Pinpoint Test U: 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 Smart Junction Box (SJB) sends a reference signal to the headlamp switch through circuit CLF21 (GY/VT). 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 provides voltage to the fog lamp relay coil through circuit CLF29 (BN). When the fog lamp relay is energized, voltage is routed through circuit CLF12 (BN/YE) to the fog lamps.
- DTC B2254 (Front Fog Lamp Switch Failure) - an on-demand DTC that sets when the SJB detects a short to ground on the fog lamp on input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Fog lamp relay
- Headlamp switch
- SJB
PINPOINT TEST U: 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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U1 CHECK THE HEADLAMP SWITCH PID
- Ignition OFF.
- Retrieve the recorded results from the SJB self-test.
- Is DTC B2254 present?
Yes
GO to U2.
No
GO to U4.
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U2 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Carry out the headlamp switch component test.
- Is the headlamp switch OK?
Yes
GO to U3.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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U3 CHECK CIRCUIT CLF21 (GY/VT) FOR A SHORT TO GROUND
- Disconnect: SJB C2280d.
- Measure the resistance between the headlamp switch C205-6, circuit CLF21 (GY/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to U9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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U4 CHECK CIRCUIT CLF12 (BN/YE) FOR A SHORT TO VOLTAGE
- Disconnect: Fog Lamp Relay.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to U5.
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U5 CHECK THE FOG LAMP RELAY
- Ignition OFF.
- Carry out the fog lamp relay component test.
- Is the fog lamp relay OK?
Yes
GO to U6.
No
INSTALL a new fog lamp relay. CLEAR the DTCs. REPEAT the self-test.
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U6 CHECK THE HEADLAMP SWITCH (SHORT TO VOLTAGE)
- Connect: Fog Lamp Relay.
- Disconnect: Headlamp Switch C205.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
GO to U7.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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U7 CHECK CIRCUIT CLF29 (BN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: SJB C2280a.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to U8.
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U8 CHECK CIRCUIT CLF28 (BN/WH) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Connect: SJB C2280a.
- Disconnect: SJB C2280d.
- Ignition OFF.
- Do the fog lamps continue to illuminate?
Yes
GO to U9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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U9 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 Body Control Systems. 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.
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