Pinpoint Test B: One Low Beam Headlamp Is Inoperative - Vehicles With Halogen Headlamps
Headlamps
Pinpoint Test B: One Low Beam Headlamp Is Inoperative - Vehicles With Halogen Headlamps
Refer to Wiring Diagram Set 11, Fuse and Relay Information for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. Diagrams By Number
Normal Operation
When the Smart Junction Box (SJB) detects the headlamp switch in the HEADLAMPS ON position, the SJB (Smart Junction Box) provides voltage to the coils of the LH and RH headlamp relays, energizing both relays. When the headlamp relays energize, voltage is supplied from the Battery Junction Box (BJB) to the headlamps.
On vehicles equipped with Daytime Running Lamps (DRL), ground for the LH headlamp is routed through the DRL (Daytime Running Lamps) relay 1.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Headlamp relay
- DRL (Daytime Running Lamps) relay 1
- Headlamp assembly
- SJB (Smart Junction Box)
PINPOINT TEST B : ONE LOW BEAM HEADLAMP IS INOPERATIVE - VEHICLES WITH HALOGEN HEADLAMPS
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
B1 CHECK THE HEADLAMP RELAY
- Ignition OFF.
- Disconnect: Suspect Headlamp Relay.
- Substitute a known good relay.
- Place the headlamp switch in the HEADLAMPS ON position.
Is the headlamp in question illuminated?
Yes
REMOVE the known good relay. INSTALL a new headlamp relay. CLEAR the DTCs. REPEAT the self-test.
No
REMOVE the known good relay. GO to B2.
B2 CHECK FOR SJB (Smart Junction Box) SUPPLIED VOLTAGE TO THE HEADLAMP RELAY
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 1, circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 1, circuit CLF05 (BU/GN), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B6.
No
VERIFY the SJB (Smart Junction Box) fuse 7 (10A) (LH low beam) or fuse 8 (10A) (RH low beam) is OK. If OK, GO to B3.
If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the low beam output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.
B3 REPEAT THE SJB (Smart Junction Box) SELF-TEST AND CHECK FOR VOLTAGE TO THE HEADLAMP
- Place the headlamp switch in the OFF position.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB (Smart Junction Box) Self-Test.
- Clear the DTCsand repeat the on-demand self-test(required to enable the low beam output driver if DTC B106E is present).
- Place the headlamp switch in the HEADLAMPS ON position.
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 1, circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 1, circuit CLF05 (BU/GN), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
INSTALL a new headlamp relay. CLEAR the DTCs. REPEAT the self-test.
No
GO to B4.
B4 CHECK THE LOW BEAM OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280E.
- For the LH headlamp, measure the resistance between the LH headlamp relay pin 1, circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the resistance between the RH headlamp relay pin 1, circuit CLF05 (BU/GN), BJB (Battery Junction Box) face side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to B5.
No
REPAIR circuit CLF04 (BN/BU) (LH low beam) or circuit CLF05 (BU/GN) (RH low beam) for a short to ground. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the low beam output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.
B5 CHECK THE LOW BEAM OUTPUT CIRCUIT FOR AN OPEN
- For an inoperative LH headlamp, measure the resistance between the LH headlamp relay pin 1, circuit CLF04 (BN/BU), BJB (Battery Junction Box) face side and the SJB (Smart Junction Box) C2280E-13, circuit CLF04 (BN/BU), harness side.
- For an inoperative RH headlamp, measure the resistance between the RH headlamp relay pin 1, circuit CLF05 (BU/GN), BJB (Battery Junction Box) face side and the SJB (Smart Junction Box) C2280E-4, circuit CLF05 (BU/GN), harness side.
Is the resistance less than 5 ohms?
Yes
GO to B12.
No
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) for an open. CLEAR the DTCs. REPEAT the self-test.
B6 CHECK FOR BJB (Battery Junction Box) SUPPLIED VOLTAGE TO THE HEADLAMP RELAY
- Place the headlamp switch in the OFF position.
- For the LH headlamp, measure the voltage between the LH headlamp relay pin 5, circuit SBB16 (VT/RD), BJB (Battery Junction Box) face side and ground.
- For the RH headlamp, measure the voltage between the RH headlamp relay pin 5, circuit SBB25 (RD), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B7.
No
VERIFY the BJB (Battery Junction Box) fuse 16 (20A) (LH low beam) or fuse 25 (20A) (RH low beam) is OK. If OK, REPAIR circuit SBB16 (VT/RD) (LH headlamp) or circuit SBB25 (RD) (RH headlamp) for an open. TEST the system for normal operation. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
B7 BYPASS THE HEADLAMP RELAY
- For an inoperative LH headlamp, connect a fused jumper wire between the LH headlamp relay pin 5, circuit SBB16 (VT/RD), BJB (Battery Junction Box) face side and the LH headlamp relay pin 3, circuit SBB16 (VT/RD), BJB (Battery Junction Box) face side.
- For an inoperative RH headlamp, connect a fused jumper wire between the RH headlamp relay pin 5, circuit SBB25 (RD), BJB (Battery Junction Box) face side and the RH headlamp relay pin 3, circuit SBB25 (RD), BJB (Battery Junction Box) face side.
Is the headlamp in question illuminated?
Yes
REMOVE the jumper wire. REPAIR the relay ground circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
No
LEAVE the jumper wire connected. GO to B8.
B8 CHECK FOR VOLTAGE TO THE HEADLAMP
- Disconnect: Inoperative Headlamp.
- Measure the voltage between the LH headlamp C1021-3, circuit SBB16 (VT/RD), harness side and ground; or between the RH headlamp C1041-3, circuit SBB25 (RD), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B9.
No
REMOVE the jumper wire. REPAIR circuit SBB16 (VT/RD) (LH headlamp) or circuit SBB25 (RD) (RH headlamp) between the relay and the headlamp for an open. TEST the system for normal operation.
B9 CHECK FOR VOLTAGE TO THE HEADLAMP USING THE CONNECTOR GROUND
- Measure the voltage between the LH headlamp C1021-3, circuit SBB16 (VT/RD), harness side and the LH headlamp C1021-2, circuit GD120 (BK/GN), harness side; or between the RH headlamp C1041-3, circuit SBB25 (RD), harness side and the RH headlamp C1041-2, circuit GD123 (BK/GY), harness side.
Is the voltage greater than 10 volts?
Yes
REMOVE the jumper wire. REPAIR or INSTALL a new headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation.
No
For the LH headlamp on vehicles equipped with DRL (Daytime Running Lamps), GO to B10.
For the LH headlamp on vehicles not equipped with DRL (Daytime Running Lamps) or the RH headlamp, REMOVE the jumper wire. REPAIR circuit GD120 (BK/GN) (LH headlamp) or circuit GD123 (BK/GY) (RH headlamp) for an open. TEST the system for normal operation.
B10 CHECK THE HEADLAMP GROUND CIRCUIT TO THE DRL (Daytime Running Lamps) RELAY 1 FOR AN OPEN
- Connect: LH Headlamp C1021.
- Disconnect: DRL (Daytime Running Lamps) Relay 1.
- Measure the voltage between the DRL (Daytime Running Lamps) relay 1 pin 3, circuit GD120 (BK/GN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to B11.
No
REMOVE the jumper wire. REPAIR circuit GD120 (BK/GN) between the LH headlamp and the DRL (Daytime Running Lamps) relay 1 for an open. TEST the system for normal operation.
B11 BYPASS THE DRL (Daytime Running Lamps) RELAY 1
- Connect a fused jumper wire between the DRL (Daytime Running Lamps) relay 1 pin 3, circuit GD120 (BK/GN), harness side and the DRL (Daytime Running Lamps) relay 1 pin 4, circuit GD120 (BK/GN), harness side.
Does the LH headlamp illuminate?
Yes
REMOVE the jumper wires. INSTALL a new DRL (Daytime Running Lamps) relay 1. TEST the system for normal operation.
No
REMOVE the jumper wires. REPAIR circuit GD120 (BK/GN) between the DRL (Daytime Running Lamps) relay 1 and ground for an open. TEST the system for normal operation.
B12 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. CLEAR the DTCs. REPEAT the self-test.