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 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 lamp on request, the SJB provides a voltage to the fog lamp relay coil through circuit CLF28 (BN/WH). The fog lamp relay coil ground is provided through circuit GD120 (BK/GN). When the fog lamp relay is energized, voltage is sent 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 from the fog lamps on input circuit.
- DTC B2512 (Front Fog Lamp Relay Ckt Short to Battery) - a continuous and on-demand DTC that sets when the SJB detects a short to voltage from the fog lamp relay coil voltage supply circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Fog lamp relay
- Headlamp switch
- SJB
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 HEADLAMP SWITCH PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- NOTE: Make sure the headlamp switch is in the OFF position.
- Monitor the SJB headlamp switch PID (FOG SW).
- Does the PID agree with the headlamp switch position?
Yes
GO to S4.
No
GO to S2.
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S2 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 S3.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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S3 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 S9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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S4 CHECK CIRCUIT CLF12 (BN/YE) FOR A SHORT TO VOLTAGE
- Disconnect: Fog Lamp Relay.
- Do the fog lamps continue to illuminate?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to S5.
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S5 CHECK THE FOG LAMP RELAY
- Substitute a known good relay.
- Do the fog lamps continue to illuminate?
Yes
REMOVE the known good relay. INSTALL the original fog lamp relay. GO to S6.
No
REMOVE the known good relay. INSTALL a new fog lamp relay. CLEAR the DTCs. REPEAT the self-test.
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S6 CHECK THE HEADLAMP SWITCH FOR A SHORT TO VOLTAGE
- Disconnect: Headlamp Switch C205.
- Do the fog lamps continue to illuminate?
Yes
GO to S7.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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S7 CHECK CIRCUIT CLF28 (BN/WH) FOR A SHORT TO VOLTAGE (TO HEADLAMP SWITCH)
- Disconnect: SJB C2280d.
- Do the fog lamps continue to illuminate?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to S8.
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S8 CHECK CIRCUIT CLF28 (BN/WH) FOR A SHORT TO VOLTAGE (TO FOG LAMP RELAY)
- Disconnect: SJB C2280e.
- Do the fog lamps continue to illuminate?
Yes
GO to S9.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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S9 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. 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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