Pinpoint Test T: The Fog Lamps Are On Continuously
Fog Lamps
Pinpoint Tests
Pinpoint Test T: 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 to monitor the fog lamp request. 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 ground to the fog lamp relay coil (integrated into the SJB). When the fog lamp relay is energized, voltage is routed to the fog lamps and to the headlamp switch for the fog lamps on indicator.
- 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
- Headlamp switch
- SJB
PINPOINT TEST T: 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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T1 CHECK FOR RECORDED SJB DTCs
- Check the recorded results from the SJB self-test.
- Is DTC B2254 present?
Yes
GO to T2.
No
GO to T4.
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T2 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Measure the voltage between the headlamp switch C205-6, circuit CLF29 (BN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
GO to T3.
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T3 CHECK THE FOG LAMP REQUEST INPUT FOR A SHORT TO GROUND
- Disconnect: SJB C2280b.
- Measure the resistance between the headlamp switch C205-6, circuit CLF29 (BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to T6.
No
REPAIR circuit CLF29 (BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
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T4 CHECK THE SJB FOG LAMPS ON INDICATOR OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: SJB C2280a.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
GO to T5.
No
REPAIR circuit CLF28 (BN/WH) for a short to voltage. TEST the system for normal operation.
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T5 CHECK THE FOG LAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: SJB C2280e.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
REPAIR circuit CLF21 (GY/VT) for a short to voltage. TEST the system for normal operation.
No
GO to T6.
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T6 CHECK FOR CORRECT SJB OPERATION
- Ignition OFF.
- 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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