Pinpoint Test F: The Headlamps Are On Continuously
Headlamps
Pinpoint Tests
Pinpoint Test F: The Headlamps Are On Continuously
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
The Smart Junction Box (SJB) sends voltage reference signals to the headlamp switch through circuits 1400 (TN/WH), 1401 (BK/LG), and 1402 (RD/WH). At any given time, the headlamp switch routes one of the input circuits to ground through circuit 1205 (BK).
When the SJB detects the headlamp switch in the HEADLAMPS ON position (or a fault with the headlamp switch inputs) and the multifunction switch in the LOW BEAM position, the SJB sends voltage through circuits 1338 (WH) and 1336 (LG/WH) to the LH and RH low beams, or the LH and RH High Intensity Discharge (HID) relays (if equipped).
When the HID relays are energized, voltage is routed to the LH and RH headlamps through circuits 2008 (PK/WH) (PK/BK for 5.4L) and 2009 (PK/WH).
The SJB also sends a voltage reference signal to the multifunction switch through circuits 1394 (WH/RD) and 1395 (RD/PK). When the multifunction switch is placed in the FLASH-TO-PASS or HIGH BEAM position, the signal is routed back to the SJB (ground internal to the SJB). When the SJB detects a request for flash-to-pass or high beams, the SJB provides ground to the high beam relay through circuit 1708 (LG/BK). When the high beam relay is energized, voltage is routed through circuits 1337 (VT/YE) and 1335 (YE/WH) to the LH and RH headlamps.
B1470-B2598:
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High beam relay
- HID relay
- Headlamp switch
- Multifunction switch
- Bussed Electrical Center (BEC)
- SJB
PINPOINT TEST F: THE HEADLAMPS 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.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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F1 DETERMINE IF THE HIGH BEAMS ARE ALWAYS ON
- Ignition ON.
- While observing the headlamps, engage the flash-to-pass feature.
- Does the headlamp brightness increase?
Yes
GO to F2.
No
GO to F13.
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F2 USE THE RECORDED DTCs FROM THE SJB SELF-TEST (LOW BEAMS ALWAYS ON)
- Record the results from the SJB self-test.
- Was DTC B1470 recorded?
Yes
GO to F3.
No
GO to F8.
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F3 CHECK THE SJB HEADLAMP SWITCH PIDs
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- NOTE: Make sure the headlamp switch is correctly lined up (in a detent position) when checking each PID.
- Monitor the SJB headlamp switch PIDs (HD_LMP_SW, P_LMP_SW, LAMP_SW) while moving the headlamp switch through all positions.
- Do the headlamp switch positions agree with the PIDs?
Yes
The system is operating correctly. The concern may have been caused by the headlamp switch between detent positions.
No
GO to F4.
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F4 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Disconnect: Headlamp Switch C205.
- Measure the resistance between the headlamp switch C205-7, circuit 1205 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to F5.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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F5 CHECK THE HEADLAMP SWITCH
- Carry out the headlamp switch component test.
- Is the headlamp switch OK?
Yes
GO to F6.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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F6 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR A SHORT TO GROUND
- Disconnect: SJB C2280b.
- Measure the resistance between the headlamp switch, harness side and ground as follows:
- Are the resistances greater than 10,000 ohms?
Yes
GO to F7.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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F7 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR AN OPEN
- Measure the resistance between the headlamp switch, harness side and the SJB, harness side as follows:
- Are the resistances less than 5 ohms?
Yes
GO to F21.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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F8 CHECK THE SJB
- Ignition OFF.
- Disconnect: SJB C2280d.
- Ignition ON.
- Does either headlamp continue to illuminate?
Yes
GO to F9.
No
GO to F21.
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F9 CHECK CIRCUITS 1336 (LG/WH) AND 1338 (WH) FOR A SHORT TO VOLTAGE (SJB TO BEC)
- Ignition OFF.
- Disconnect: BEC C1035a.
- Ignition ON.
- Does either headlamp continue to illuminate?
Yes
GO to F10.
No
REPAIR circuit 1338 (WH) (LH headlamp) or circuit 1336 (LG/WH) (RH headlamp). CLEAR the DTCs. REPEAT the self-test.
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F10 CHECK CIRCUITS 1336 (LG/WH) AND 1338 (WH) FOR A SHORT TO VOLTAGE (BEC TO HEADLAMP) (HALOGEN HEADLAMPS)
- Ignition OFF.
- Disconnect: BEC C1035c.
- Ignition ON.
- Does either headlamp continue to illuminate?
Yes
For halogen headlamps, REPAIR circuit 1338 (WH) (LH headlamp) or circuit 1336 (LG/WH) (RH headlamp). CLEAR the DTCs. REPEAT the self-test.
For HID headlamps, GO to F11.
No
INSTALL a new BEC. CLEAR the DTCs. REPEAT the self-test.
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F11 CHECK CIRCUITS 2008 (PK/BK) (PK/BK FOR 5.4L) AND 2009 (PK/WH) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Suspect HID Relay.
- Ignition ON.
- Does the headlamp in question continue to illuminate?
Yes
REPAIR circuit 2008 (PK/WH) (PK/BK for 5.4L) or circuit 2009 (PK/WH) (RH headlamp). TEST the system for normal operation.
No
GO to F12.
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F12 CHECK CIRCUITS 1336 (LG/WH) AND 1338 (WH) FOR A SHORT TO VOLTAGE (BEC TO HEADLAMP) (HID HEADLAMPS)
- For 4.0L or 4.6L vehicles, measure the voltage between the LH HID relay pin 2, circuit 1338 (WH), harness side and ground; or between the RH HID relay pin 2, circuit 1336 (LG/WH), harness side and ground.
- For 5.4L vehicles, measure the voltage between the LH HID relay pin 1, circuit 1338 (WH), harness side and ground; or between the RH HID relay pin 1, circuit 1336 (LG/WH), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit 1338 (WH) (LH headlamp) or circuit 1336 (LG/WH) (RH headlamp). CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new HID relay. TEST the system for normal operation.
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F13 USE THE RECORDED DTCs FROM THE SJB SELF-TEST (HIGH BEAMS ALWAYS ON)
- Retrieve the recorded results from the SJB self-test.
- Was DTC B2586 or B2598 recorded?
Yes
For DTC B2586, GO to F14.
For DTC B2598, GO to F17.
No
GO to F19.
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F14 CHECK THE MULTIFUNCTION SWITCH
- Ignition OFF.
- Disconnect: Multifunction Switch C202.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the SJB DTCs. Repeat the SJB on-demand self-test.
- Is DTC B2586 still present?
Yes
GO to F15.
No
INSTALL a new multifunction switch. CLEAR the DTCs. REPEAT the self-test.
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F15 CHECK CIRCUITS 1394 (WH/RD) AND 1395 (RD/PK) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the SJB C2280b-45, circuit 1394 (WH/RD), harness side and ground; and between the SJB C2280b-40, circuit 1395 (RD/PK), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F16.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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F16 CHECK CIRCUITS 1394 (WH/RD) AND 1395 (RD/PK) FOR A SHORT TO CIRCUIT 1396 (VT/WH)
- Measure the resistance between the SJB C2280b-45, circuit 1394 (WH/RD), harness side and the SJB C2280b-4, circuit 1396 (VT/WH), harness side; and between the SJB C2280b-40, circuit 1395 (RD/PK), harness side and the SJB C2280b-4, circuit 1396 (VT/WH), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F21.
No
REPAIR the circuits in question. CLEAR the DTCs. REPEAT the self-test.
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F17 CHECK THE SJB HIGH BEAM CONTROL
- Disconnect: SJB C2280c.
- Ignition ON.
- Do the headlamps continue to illuminate?
Yes
GO to F18.
No
GO to F21.
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F18 CHECK CIRCUIT 1708 (LG/BK) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BEC C1035a.
- Ignition ON.
- Do the headlamps continue to illuminate?
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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F19 CHECK THE HIGH BEAM RELAY
- Disconnect: High Beam Relay.
- Ignition ON.
- Do the headlamps continue to illuminate?
Yes
GO to F20.
No
INSTALL a new high beam relay. TEST the system for normal operation.
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F20 CHECK CIRCUITS 1335 (YE/WH) AND 1337 (VT/YE) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BEC C1035c.
- Ignition ON.
- Does either headlamp continue to illuminate?
Yes
REPAIR circuit 1337 (VT/YE) (LH headlamp) or circuit 1335 (YE/WH) (RH headlamp). TEST the system for normal operation.
No
INSTALL a new BEC. TEST the system for normal operation.
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F21 CHECK FOR CORRECT SJB OPERATION
- Ignition OFF.
- 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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