Pinpoint Test T: Both Fog Lamps Are Inoperative
Fog Lamps
Pinpoint Test T: Both Fog Lamps Are Inoperative
Normal Operation
The Smart Junction Box (SJB) sends a voltage 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 (Smart Junction Box) detects the fog lamps on request, the SJB (Smart Junction Box) energizes the fog lamp relay (integrated into the SJB (Smart Junction Box)).
When the fog lamp relay is energized on vehicles without the automatic high beam feature, voltage is routed to the fog lamps.
When the fog lamp relay is energized on vehicles with the automatic high beam feature, voltage is routed to the fog lamps deactivation relay (located in the Battery Junction Box (BJB)). When the high beams are not on, voltage passes through the relay to the fog lamps.
The fog lamps share a common ground.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Fog lamps deactivation relay (if equipped)
- Headlamp switch
- SJB (Smart Junction Box)
PINPOINT TEST T : BOTH 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.
T1 CHECK THE SJB (Smart Junction Box) FOG LAMP SWITCH PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB (Smart Junction Box) DataLogger.
- Monitor the SJB (Smart Junction Box) fog lamp PID (FOG SW) while engaging the fog lamp switch.
Does the PID indicate the fog lamp switch is on?
Yes
GO to T4.
No
GO to T2.
T2 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Ignition ON.
- Measure the voltage between the headlamp switch C205-6, circuit CLF18 (BU/WH), harness side and ground.
Is the voltage greater than 10 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch . TEST the system for normal operation.
No
GO to T3.
T3 CHECK THE FOG LAMPS REQUEST INPUT CIRCUIT FOR AN OPEN
- Disconnect: SJB (Smart Junction Box) C2280B.
- Measure the resistance between the headlamp switch C205-6, circuit CLF18 (BU/WH), harness side and the SJB (Smart Junction Box) C2280B-49, circuit CLF18 (BU/WH), harness side.
Is the resistance less than 5 ohms?
Yes
GO to T9.
No
REPAIR circuit CLF18 (BU/WH) for an open. TEST the system for normal operation.
T4 CHECK FOR VOLTAGE TO THE FOG LAMPS
- Ignition OFF.
- Disconnect: LH Fog Lamp C152.
- Ignition ON.
- Place the headlamp switch in the PARKING LAMPS ON position and engage the fog lamp switch.
- Measure the voltage between the LH fog lamp C152-A, circuit CLF12 (BN/YE), harness side and ground.
Is the voltage greater than 10 volts?
Yes
REPAIR circuit GD123 (BK/GY) for an open. TEST the system for normal operation.
No
For vehicles equipped with the automatic high beam feature, GO to T5.
For vehicles not equipped with the automatic high beam feature, VERIFY the SJB (Smart Junction Box) fuse 21 (15A) is OK. If OK, GO to T8. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Electrical Diagrams
T5 CHECK FOR VOLTAGE TO THE FOG LAMPS DEACTIVATION RELAY
- Connect: LH Fog Lamp C152.
- Disconnect: Fog Lamps Deactivation Relay.
- Measure the voltage between the fog lamps deactivation relay pin 4, circuit CLF28 (BN/WH), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to T7.
No
VERIFY the SJB (Smart Junction Box) fuse 21 (15A) is OK. If OK, GO to T6. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Electrical Diagrams
T6 CHECK THE FOG LAMPS SUPPLY CIRCUIT FOR AN OPEN TO THE FOG LAMPS DEACTIVATION RELAY
- Connect: Fog Lamps Deactivation Relay.
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280E.
- Connect a fused jumper wire between the SJB (Smart Junction Box) C2280E-1, circuit CDC34 (WH/OG) (without Intelligent Access (IA)) or CBB36 (BU/BN) (with IA (Intelligent Access)), harness side and the SJB (Smart Junction Box) C2280E-3, circuit CLF28 (BN/WH), harness side.
- Ignition ON.
Do the fog lamps illuminate?
Yes
REMOVE the jumper wire. GO to T9.
No
REMOVE the jumper wire. REPAIR circuit CLF28 (BN/WH) for an open. TEST the system for normal operation.
T7 BYPASS THE FOG LAMPS DEACTIVATION RELAY
- Ignition OFF.
- Connect a fused jumper wire between the fog lamps deactivation relay pin 4, circuit CLF28 (BN/WH), BJB (Battery Junction Box) face side and fog lamps deactivation relay pin 3, circuit CLF12 (BN/YE), BJB (Battery Junction Box) face side.
- Ignition ON.
Do the fog lamps illuminate?
Yes
REMOVE the jumper wire. INSTALL a new fog lamps deactivation relay. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit CLF12 (BN/YE) for an open. TEST the system for normal operation.
T8 CHECK THE FOG LAMPS VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Connect: LH Fog Lamp C152.
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280E.
- Connect a fused jumper wire between the SJB (Smart Junction Box) C2280E-1, circuit CDC34 (WH/OG) (without Intelligent Access (IA)) or CBB36 (BU/BN) (with IA (Intelligent Access)), harness side and the SJB (Smart Junction Box) C2280E-3, circuit CLF12 (BN/YE), harness side.
- Ignition ON.
Do the fog lamps illuminate?
Yes
REMOVE the jumper wire. GO to T9.
No
REMOVE the jumper wire. REPAIR circuit CLF12 (BN/YE) for an open. TEST the system for normal operation.
T9 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION
- Disconnect all the SJB (Smart Junction Box) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB (Smart Junction Box) 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 (Smart Junction Box). 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.