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.
(Without daytime light system) power then flows to the front combination lamp LH and RH low beams.
(With daytime light system) power then flows to the front combination lamp LH low beam and the daytime light relay 2 which becomes energized and then power is sent to the front combination lamp RH low beam.


Component Function Check


1. CHECK HEADLAMP (LO) OPERATION

WITHOUT CONSULT
1.Start IPDM E/R auto active test. Diagnosis Description.
2.Check that the headlamp is turned ON.
CONSULT
1.Select "EXTERNAL LAMPS" of IPDM E/R active test item.
2.With the test items operating, check that the headlamp is turned ON.

LO: Headlamp ON
OFF: Headlamp OFF

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


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- Replace the fuse after repairing the affected circuit.
NO- GO TO 2.

2. CHECK LOW BEAM BULB

Check the applicable low beam bulb to be sure the proper bulb standard is in use and the bulb is not open.
Is the bulb OK?
YES- GO TO 3.
NO- Replace the bulb.

3. CHECK HEADLAMP (LO) OUTPUT VOLTAGE

1.Turn the ignition switch OFF.
2.Disconnect the front combination lamp connector E25 or E26.
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 battery voltage present?
YES- GO TO 9.
NO- GO TO 4 (without daytime light system).
- GO TO 5 (with daytime light system).

4. CHECK HEADLAMP (LO) CIRCUIT FOR OPEN

1.Turn the ignition switch OFF.
2.Disconnect IPDM E/R connector E44.
3.Check continuity between the IPDM E/R harness connector E44 and the front combination lamp harness connectors E25 and E26.





Does continuity exist?
YES- Replace IPDM E/R. Service and Repair.
NO- Repair the harnesses or connectors.

5. CHECK DAYTIME LIGHT RELAY 2 TO FRONT COMBINATION LAMP RH CIRCUIT FOR OPEN

1.Disconnect daytime light relay 2 connector E38.
2.Check continuity between the daytime light relay 2 harness connector E38 and the front combination lamp
LH harness connector E25.





Does continuity exist?
YES- GO TO 6.
NO- Repair the harnesses or connectors.

6. CHECK DAYTIME LIGHT RELAY 2 VOLTAGE CIRCUIT

1.With the low beam headlamps ON, check the voltage between the daytime light relay 2 connector E38
and ground.





Is battery voltage present?
YES- GO TO 7.
NO- GO TO 8.

7. CHECK DAYTIME LIGHT RELAY 2 GROUND CIRCUIT

Check continuity between the daytime light relay 2 harness connector E38 and ground.





Does continuity exist?
YES- Replace daytime light relay 2.
NO- Repair the harness or connector.

8. CHECK IPDM E/R TO DAYTIME LIGHT RELAY 2 CIRCUIT FOR OPEN

1.Disconnect IPDM E/R connector E44.
2.Check continuity between the daytime light relay 2 harness connector E38 and the IPDM E/R connector
E44.





Does continuity exist?
YES- Replace IPDM E/R. Service and Repair.
NO- Repair the harnesses or connectors.

9. CHECK FRONT COMBINATION LAMP (LO) GROUND CIRCUIT

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





Does continuity exist?
YES- Replace malfunctioning lamp.
NO- Repair the harness or connector (without daytime light system).
- GO TO 10 (with daytime light system).

10. CHECK FRONT COMBINATION LAMP RH TO DAYTIME LIGHT RELAY 1 GROUND CIRCUIT

1.Disconnect daytime light relay 1 connector E37.
2.Check continuity between the daytime light relay 1 harness connector E37 and the front combination lamp
LH harness connector E25.





Does continuity exist?
YES- GO TO 11.
NO- Repair the harnesses or connectors.

11. CHECK DAYTIME LIGHT RELAY 1 GROUND CIRCUIT

Check continuity between the daytime light relay 1 harness connector E37 and ground.





Does continuity exist?
YES- Replace daytime light relay 1.
NO- Repair the harness or connector.