Pinpoint Test D: The Low Beam(s) Are Always On
Headlamps
Pinpoint Tests
Pinpoint Test D: The Low Beam(s) Are Always On
Refer to Wiring Diagram Set 85, Headlamps for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) sends voltage signals to the headlamp switch for the OFF, PARKING LAMP ON and HEADLAMP ON positions. At any given time, the headlamp switch routes one of the input circuits to ground. If the SJB detects multiple inputs active or no inputs active for 5 seconds, the SJB turns the parking lamps and headlamps on.
When the SJB detects the headlamp switch in the HEADLAMPS ON position with the multifunction switch in the LOW BEAM position, the SJB provides voltage to the LH and RH low beam headlamps.
B2A2E-B2498:
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Headlamp switch
- SJB
PINPOINT TEST D: THE LOW BEAM(S) ARE ALWAYS ON
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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D1 CHECK FOR DTC B2008
- Review the DTCs retrieved from the SJB self-test.
- Is DTC B2008 present?
Yes
GO to Pinpoint Test G. Pinpoint Test G: DTC B2008
No
GO to D2.
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D2 CHECK THE SJB HEADLAMP SWITCH PIDs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- NOTE: Make sure the headlamp switch is lined up in the correct position when monitoring the PIDs.
- NOTE: Only one PID should indicate ON at each headlamp switch position.
- Monitor the SJB headlamp switch PIDs (HDLMP_OFF_CKT, HDLMP_PRK_CKT, HDLMP_ON_CKT) while moving the headlamp switch through all positions.
- Do the headlamp switch positions agree with the PIDs?
Yes
GO to D7.
No
GO to D3.
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D3 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Measure the voltage between the headlamp switch, harness side and ground as follows:
- Is the voltage greater than 10 volts?
Yes
GO to D4.
No
GO to D5.
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D4 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH USING THE CONNECTOR GROUND
- Measure the voltage between the headlamp switch C205-4, circuit CLF23 (WH/VT), harness side and the headlamp switch C205-1, circuit GD134 (BK/VT), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD134 (BK/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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D5 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:
- Is the resistance greater than 10,000 ohms?
Yes
GO to D6.
No
REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.
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D6 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 D8.
No
REPAIR the circuit in question for an open. CLEAR the DTCs. REPEAT the self-test.
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D7 CHECK THE SJB OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280e.
- Does the LH or RH headlamp continue to illuminate?
Yes
REPAIR circuit CLF04 (BN/BU) (LH headlamp) or circuit CLF05 (BU/GN) (RH headlamp) for a short to voltage as necessary. CLEAR the DTCs. REPEAT the self-test.
No
GO to D8.
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D8 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. 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.
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