Pinpoint Test S: The Fog Lamps Are Inoperative
Fog Lamps
Pinpoint Tests
Pinpoint Test S: The Fog Lamps Are Inoperative
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.
Voltage is supplied to the switched side of the fog lamp relay from the Battery Junction Box (BJB) fuse 24 (15A) through circuit SBB24 (VT/RD).
When the SJB detects the fog lamps on request, the SJB provides voltage to the fog lamp relay coil through circuit CLF29 (BN). The fog lamp relay coil ground is provided through circuit GD121 (BK/YE). When the fog lamp relay is energized, voltage is routed through circuit CLF12 (BN/YE) to the fog lamps.
- DTC B2030 (Front Fog Lamp Relay CKT Failure) - a continuous DTC that sets when the SJB detects a short to ground on the fog lamp relay coil voltage supply circuit.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Fog lamp relay
- Headlamp switch
- SJB
PINPOINT TEST S: THE FOG LAMPS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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S1 CHECK THE HEADLAMP SWITCH PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB fog lamp switch PID (FOG SW) while engaging the fog lamp switch.
- Does the PID indicate the fog lamp switch is active?
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. TEST the system for normal operation.
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S3 CHECK CIRCUIT CLF21 (GY/VT) FOR AN OPEN
- Disconnect: SJB C2280d.
- Measure the resistance between the headlamp switch C205-6, circuit CLF21 (GY/VT), harness side and the SJB C2280d-28, circuit CLF21 (GY/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to S10.
No
REPAIR the circuit. TEST the system for normal operation.
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S4 CHECK THE FOG LAMP RELAY
- Ignition OFF.
- Disconnect: Fog Lamp Relay.
- Substitute a known good relay and recheck the fog lamp operation.
- Do the fog lamps operate correctly?
Yes
REMOVE the known good relay. INSTALL a new fog lamp relay. CLEAR the DTCs. REPEAT the self-test.
No
REMOVE the known good relay. GO to S5.
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S5 CHECK CIRCUIT CLF29 (BN) FOR VOLTAGE
- Ignition ON.
- Place the headlamp switch in the HEADLAMPS ON position and engage the fog lamp switch.
- Measure the voltage between the fog lamp relay pin 86, circuit CLF29 (BN), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
PLACE the headlamp switch in the OFF position. GO to S8.
No
PLACE the headlamp switch in the OFF position. GO to S6.
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S6 CHECK CIRCUIT CLF29 (BN) FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280a.
- Measure the resistance between the fog lamp relay pin 86, circuit CLF29 (BN), BJB face side and the SJB C2280a-10, circuit CLF29 (BN), harness side; and between the fog lamp relay pin 86, circuit CLF29 (BN), BJB face side and ground.
- Is the resistance less than 5 ohms between the fog lamp relay and the SJB, and greater than 10,000 ohms between the fog lamp relay and ground?
Yes
GO to S7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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S7 CHECK CIRCUIT CLF28 (BN/WH) FOR A SHORT TO GROUND
- Disconnect: SJB C2280d.
- Disconnect: Headlamp Switch C205.
- Measure the resistance between the headlamp switch C205-7, circuit CLF28 (BN/WH), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S10.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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S8 CHECK CIRCUIT SBB24 (VT/RD) FOR AN OPEN
- Ignition OFF.
- Measure the voltage between the fog lamp relay pin 30, circuit SBB24 (VT/RD), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to S9.
No
VERIFY the BJB fuse 24 (15A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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S9 CHECK CIRCUIT GD121 (BK/YE) FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the fog lamp relay pin 85, circuit GD121 (BK/YE), BJB face side and ground.
- Is the resistance less than 5 ohms?
Yes
REPAIR circuit CLF12 (BN/YE) for an open. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD121 (BK/YE) for an open. CLEAR the DTCs. REPEAT the self-test.
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S10 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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