Pinpoint Test D: The Low Beams Are Always On
Headlamps
Pinpoint Test D: The Low Beams Are Always On
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information Electrical Diagrams.
Normal Operation
The Smart Junction Box (SJB) sends voltage signals to the headlamp switch to monitor the OFF, PARKING LAMPS ON and HEADLAMPS ON positions. At any given time, the headlamp switch routes one of the input circuits to ground.
When the SJB (Smart Junction Box) detects the headlamp switch in the HEADLAMPS ON position with the multifunction switch in the LOW BEAM position, the SJB (Smart Junction Box) provides voltage to the LH and RH low beam headlamps.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Headlamp switch
- SJB (Smart Junction Box)
PINPOINT TEST D : THE LOW BEAMS 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.
D1 CHECK FOR AUTOLAMP DTCs
- Review the DTCs retrieved from the SJB (Smart Junction Box) self-test.
Is DTC B1696, B1791, B1793 or B2008 present?
Yes
GO to Pinpoint Test H Pinpoint Test H: The Autolamps Are On Continuously.
No
If equipped with autolamps, GO to D2.
If not equipped with autolamps, GO to D3.
D2 CHECK THE SJB (Smart Junction Box) AUTOLAMP ON REQUEST PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB (Smart Junction Box) Data Logger.
- NOTE: Make sure the headlamp switch is in the OFF position.
Monitor the SJB (Smart Junction Box) headlamp switch PID (HDLMP_AUT_CKT).
Does the PID indicate ON?
Yes
GO to Pinpoint Test H Pinpoint Test H: The Autolamps Are On Continuously.
No
GO to D3.
D3 CHECK THE SJB (Smart Junction Box) HEADLAMP SWITCH PIDs
NOTE: Make sure the headlamp switch is lined up in the correct position when monitoring the PIDs.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB (Smart Junction Box) DataLogger.
- NOTE: Only one PID should indicate ON at each headlamp switch position.
Monitor the SJB (Smart Junction Box) 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 D8.
No
GO to D4.
D4 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:
Headlamp Switch Connector-Pin Circuit C205-9 CLF23 (WH/VT) C205-5 CLS05 (BU/GY) C205-10 CLF24 (YE/BU)
Are the voltages greater than 10 volts?
Yes
GO to D5.
No
GO to D6.
D5 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH USING THE CONNECTOR GROUND
- Measure the voltage between the headlamp switch C205-9, circuit CLF23 (WH/VT), harness side and the headlamp switch C205-7, circuit GD114 (BK/BU), harness side.
Is the voltage greater than 10 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch . CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD114 (BK/BU) for an open. CLEAR the DTCs. REPEAT the self-test.
D6 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR A SHORT TO GROUND
- Disconnect: SJB (Smart Junction Box) C2280B.
- Measure the resistance between the headlamp switch, harness side and ground as follows:
Headlamp Switch Connector-Pin Circuit C205-9 CLF23 (WH/VT) C205-5 CLS05 (BU/GY) C205-10 CLF24 (YE/BU)
Are the resistances greater than 10,000 ohms?
Yes
GO to D7.
No
REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.
D7 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR AN OPEN
- Measure the resistance between the headlamp switch, harness side and the SJB (Smart Junction Box), harness side as follows:
Headlamp Switch Connector-Pin SJB (Smart Junction Box) Connector-Pin Circuit C205-9 C2280B-47 CLF23 (WH/VT) C205-5 C2280B-31 CLS05 (BU/GY) C205-10 C2280B-30 CLF24 (YE/BU)
Are the resistances less than 5 ohms?
Yes
GO to D9.
No
REPAIR the circuit in question for an open. CLEAR the DTCs. REPEAT the self-test.
D8 CHECK THE SJB (Smart Junction Box) OUTPUT
- Disconnect: SJB (Smart Junction Box) 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 D9.
D9 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION
- Ignition OFF.
- 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.