Pinpoint Test R: The Fog Lamps Are On Continuously
Fog Lamps
Pinpoint Tests
Pinpoint Test R: The Fog Lamps Are On Continuously
Refer to Wiring Diagram Set 86, Fog Lamps for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 11, Fuse and Relay Information for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) sends a voltage reference signal to the headlamp switch through circuit 1669 (OG/LG). When the fog lamp switch is engaged, the voltage signal is routed to ground. The fog lamp relay is provided voltage through the Bussed Electrical Center (BEC). When the ignition switch is in the ON position, the parking lamps are on, and the SJB detects a request for the fog lamps, the SJB provides a ground for the fog lamp relay coil through circuit 1347 (DB/WH). When the relay is energized, voltage is routed through circuits 1721 (LB/BK) and 1776 (TN/OG) to the LH and RH fog lamps, respectively.
- DTC B2030 (Front Fog Lamp Relay Ckt Failure) - a continuous and on-demand DTC that sets when the SJB detects a short to ground from the fog lamp relay coil ground controlled circuit.
- DTC B2254 (Front Fog Lamp Switch Failure) - an on-demand DTC that sets when the SJB detects a short to ground from the fog lamp switch input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Fog lamp relay
- Headlamp switch
- BEC
- SJB
PINPOINT TEST R: 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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R1 RETRIEVE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Ignition OFF.
- Retrieve the recorded results from the SJB self-test.
- Was DTC B2030 or B2254 present?
Yes
For DTC B2254, GO to R2.
For DTC B2030, GO to R4.
No
GO to R6.
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R2 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 R3.
No
INSTALL a new headlamp switch. CLEAR the DTCs. REPEAT the self-test.
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R3 CHECK CIRCUIT 1669 (OG/LG) FOR A SHORT TO GROUND
- Disconnect: SJB C2280b.
- Measure the resistance between the headlamp switch C205-6, circuit 1669 (OG/LG), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to R9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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R4 CHECK THE SJB
- Disconnect: SJB C2280c.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
GO to R5.
No
GO to R9.
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R5 CHECK CIRCUIT 1347 (DB/WH) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BEC C1035a.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
INSTALL a new BEC. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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R6 CHECK THE FOG LAMP RELAY
- Disconnect: Fog Lamp Relay.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
GO to R7.
No
INSTALL a new fog lamp relay. TEST the system for normal operation.
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R7 CHECK CIRCUIT 2024 (VT/OG) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BEC C1035a.
- Ignition ON.
- Do the fog lamps continue to illuminate?
Yes
GO to R8.
No
REPAIR the circuit. TEST the system for normal operation.
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R8 CHECK CIRCUITS 1721 (LB/BK) (LH FOG LAMP) AND 1776 (TN/OG) (RH FOG LAMP) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BEC C1035c.
- Ignition ON.
- For 4.0L or 4.6L, measure the voltage between the LH fog lamp C152-1, circuit 1721 (LB/BK), harness side and ground; or between the RH fog lamp C162-1, circuit 1776 (TN/OG), harness side and ground.
- For 5.4L, measure the voltage between the LH fog lamp C1322-A, circuit 1721 (LB/BK), harness side and ground; or between the RH fog lamp C1323-A, circuit 1776 (TN/OG), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
INSTALL a new BEC. TEST the system for normal operation.
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R9 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. 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 the DTCs. REPEAT the self-test.
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