Pinpoint Test B: Both High Beams Are Inoperative
Headlamps
Pinpoint Tests
Pinpoint Test B: Both High Beams Are Inoperative
Refer to Wiring Diagram Set 85, Headlamps 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
When the headlamp switch is placed in the HEADLAMPS ON position, the Smart Junction Box (SJB) monitors the multifunction switch by sending a voltage reference signal through circuit 1394 (WH/RD). When the multifunction switch is placed in the HIGH BEAM position, the signal is routed to an internal ground within the SJB through circuit 1396 (VT/WH). The SJB then supplies ground for the high beam relay coil through circuit 1708 (LG/BK). The high beam relay is supplied voltage at all times from the Bussed Electrical Center (BEC). When the high beam relay is energized, voltage is routed to the high beams.
If the SJB is not configured for the correct headlamp type, the high beams may be inoperative.
- DTC B2586 (Headlamp Mode Select Circuit Failure) - an on-demand DTC that sets when the SJB detects a short to ground from the multifunction switch input (headlamp mode select) circuit.
- DTC B2598 (Headlamp Relay Circuit Failure) - a continuous and on-demand DTC that sets when the SJB detects an open or short to voltage from the high beam relay coil ground controlled circuit.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- SJB configuration
- High beam relay
- Multifunction switch
- BEC
- SJB
PINPOINT TEST B: BOTH HIGH BEAMS ARE INOPERATIVE
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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B1 CHECK THE LOW BEAMS
- Ignition OFF.
- Place the headlamp switch in the HEADLAMPS ON position.
- Do the low beams illuminate?
Yes
GO to B2.
No
Go To Pinpoint Test A. Pinpoint Test A: Both Low Beams Are Inoperative
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B2 USE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Place the headlamp switch in the OFF position.
- Retrieve the recorded results from the SJB self-test.
- Was DTC B2598 or B2586 present?
Yes
For DTC B2598, GO to B3.
For DTC B2586, GO to B9.
No
GO to B11.
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B3 CHECK THE HIGH BEAM RELAY (DTC B2598)
- Disconnect: High Beam Relay.
- Substitute a known good relay and recheck the operation of the high beams.
- Do the high beams operate correctly?
Yes
REMOVE the known good relay. INSTALL a new high beam relay. CLEAR the DTCs. REPEAT the self-test.
No
REMOVE the known good relay. GO to B4.
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B4 CHECK THE HIGH BEAM RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280c.
- Ignition ON.
- Measure the voltage between the high beam relay pin 86, circuit 1708 (LG/BK), BEC face side and ground.
- Is any voltage present?
Yes
GO to B5.
No
GO to B6.
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B5 CHECK CIRCUIT 1708 (LG/BK) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BEC C1035a.
- Ignition ON.
- Measure the voltage between the high beam relay pin 86, circuit 1708 (LG/BK), BEC face side and ground.
- Is any voltage present?
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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B6 CHECK THE VOLTAGE FEED TO THE HIGH BEAM RELAY COIL
- Ignition OFF.
- Measure the voltage between the high beam relay pin 85, BEC face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to B7.
No
VERIFY the BEC fuse 50 (15A) is OK. If OK, INSTALL a new BEC. 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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B7 CHECK THE HIGH BEAM RELAY CONTROL CIRCUIT FOR AN OPEN
- Measure the resistance between the high beam relay pin 86, circuit 1708 (LG/BK), BEC face side and the SJB C2280c-1, circuit 1708 (LG/BK), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to B15.
No
GO to B8.
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B8 CHECK CIRCUIT 1708 (LG/BK) FOR AN OPEN
- Disconnect: BEC C1035a.
- Measure the resistance between the BEC C1035a-B11, circuit 1708 (LG/BK), harness side and the SJB C2280c-1, circuit 1708 (LG/BK), harness side.
- Is the resistance less than 5 ohms?
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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B9 CHECK THE MULTIFUNCTION SWITCH
- Disconnect: Multifunction Switch C202.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Repeat the SJB on-demand self-test.
- Is DTC B2586 retrieved again?
Yes
GO to B10.
No
INSTALL a new multifunction switch. TEST the system for normal operation.
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B10 CHECK CIRCUITS 1394 (WH/RD) FOR A SHORT TO GROUND
- Ignition OFF.
- Place the headlamp switch in the OFF position.
- Disconnect: SJB C2280b.
- Measure the resistance between the SJB C2280b-45, circuit 1394 (WH/RD), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to B15.
No
REPAIR the circuit. TEST the system for normal operation.
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B11 CHECK THE HIGH BEAM SWITCH INPUT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB multifunction switch status PID (HBEAMSW) while placing the multifunction switch in the HIGH BEAM position.
- Does the PID indicate HIGH BEAM position is active?
Yes
GO to B12.
No
GO to B13.
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B12 CHECK THE HIGH BEAM RELAY (NO DTCs)
- Ignition OFF.
- Place the headlamp switch in the OFF position
- Disconnect: High Beam Relay.
- Substitute a known good relay and recheck the operation on the high beams.
- Do the high beams operate correctly?
Yes
REMOVE the known good relay. INSTALL a new high beam relay. TEST the system for normal operation.
No
REMOVE the known good relay. INSTALL a new BEC. TEST the system for normal operation.
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B13 CHECK THE MULTIFUNCTION SWITCH
- Ignition OFF.
- Disconnect: Multifunction Switch C202.
- Ignition ON.
- Connect a fused jumper wire between the multifunction switch C202-8, circuit 1394 (WH/RD), harness side and the multifunction switch C202-10, circuit 1396 (VT/WH), harness side.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB multifunction switch status PID (HBEAMSW).
- Does the PID indicate HIGH BEAM position is active?
Yes
REMOVE the jumper wire. INSTALL a new multifunction switch. TEST the system for normal operation.
No
REMOVE the jumper wire. GO to B14.
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B14 CHECK CIRCUITS 1394 (WH/RD) AND 1396 (VT/WH) FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the SJB C2280b-45, circuit 1394 (WH/RD), harness side and the multifunction switch C202-8, circuit 1394 (WH/RD), harness side.
- Measure the resistance between the SJB C2280b-4, circuit 1396 (VT/WH) and the multifunction switch C202-10, circuit 1396 (VT/WH).
- Are the resistances less than 5 ohms?
Yes
GO to B15.
No
REPAIR the circuit in question. TEST the system for normal operation.
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B15 CHECK THE HIGH BEAM SWITCH INPUT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- NOTE: Vehicles equipped with halogen headlamps should display Non HID. Vehicles with HID headlamp should display HID Active Mode.
-
- Monitor the SJB headlamp configuration PID (HID Status).
- Is the configuration correct for the vehicle build?
Yes
GO to B16.
No
CONFIGURE the module using as-built data. TEST the system for normal operation.
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B16 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 the DTCs. REPEAT the self-test.
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