Headlamp (LO) Circuit

HEADLAMP (LO) CIRCUIT





Description
The IPDM E/R (intelligent power distribution module engine room) controls the headlamp low relay based on inputs from the BCM via the CAN communication lines. When the headlamp low relay is energized, power flows through fuses 40 and 41, located in the IPDM E/R. Power then flows to the front combination lamps to the headlamp low beam.




Component Function Check
1.CHECK HEADLAMP (LO) OPERATION
WITHOUT CONSULT-III
1. Start IPDM E/R auto active test. Diagnosis Description.
2. Check that the headlamp is turned ON.

NOTE:
HI/LO is repeated 1 second each when using the IPDM E/R auto active test.
CONSULT-III
1. Select "EXTERNAL LAMPS" of IPDM E/R active test item.
2. With the test items operating, check that the headlamp is turned ON.





Is the headlamp turned ON?
YES - Headlamp (LO) is normal.
NO - SEE Diagnosis Procedure.




Diagnosis Procedure
Regarding Wiring Diagram information, [1][2]Electrical Diagrams.
1.CHECK HEADLAMP (LO) FUSES
1. Turn the ignition switch OFF.
2. Check that the following fuses are not open.





Is the fuse open?
YES - Repair the harness and replace the fuse.
NO - GO TO 2.
2.CHECK HEADLAMP (LO) OUTPUT VOLTAGE





1. Turn the ignition switch OFF.
2. Disconnect the front combination lamp connector.
3. Turn the ignition switch ON.
4. Turn the low beam headlamps ON.
5. With the low beam headlamps ON, check the voltage between the combination lamp connector and ground.










Is voltage reading as specified?
YES - GO TO 4.
NO - GO TO 3.
3.CHECK HEADLAMP (LO) CIRCUIT FOR OPEN





1. Turn the ignition switch OFF.
2. Disconnect IPDM E/R connector E123.
3. Check continuity between the IPDM E/R harness connector (A) and the front combination lamp harness connector (B).





Does continuity exist?
YES - Replace IPDM E/R. Service and Repair
NO - Repair the harnesses or connectors.
4.CHECK FRONT COMBINATION LAMP (LO) GROUND CIRCUIT





Check continuity between the front combination lamp harness connector terminal and ground.





Does continuity exist?
YES - Inspect the headlamp bulb.
NO - Repair the harness.