Turn Signal Lamp Circuit

TURN SIGNAL LAMP CIRCUIT

Description

The BCM monitors inputs from the combination switch to determine when to activate the turn signals. The
BCM outputs voltage direction to the left and right turn signals during turn signal operation or both during hazard warning operation. The BCM sends a turn signal indicator request to the combination meter via the CAN
communication lines.
The BCM performs the fast flasher operation (fail-safe) if any bulb or harness of the turn signal lamp circuit is open.
NOTE:
Turn signal lamp blinks at normal speed when using the hazard warning lamp.


Component Function Check


1. CHECK TURN SIGNAL LAMP

CONSULT
1.Select FLASHER of BCM (FLASHER) active test item.
2.With operating the test items, check that the turn signal lamp blinks.

LH: Turn signal lamps (LH) ON
RH: Turn signal lamps (RH) ON
OFF: The turn signal lamps OFF

Does the turn signal lamp blink?
YES- Turn signal lamp circuit is normal.
NO- Refer to "Diagnosis Procedure" .


Diagnosis Procedure

Regarding Wiring Diagram information, refer to "Wiring Diagram" [1][2]Electrical Diagrams.

1. CHECK TURN SIGNAL LAMP BULB

Check the applicable lamp bulb to be sure the proper bulb standard is in use and the bulb is not open.
Is the bulb OK?
YES- GO TO 2.
NO- Replace the bulb.

2. CHECK TURN SIGNAL LAMP OUTPUT VOLTAGE

1.Turn the ignition switch OFF.
2.Disconnect the front or rear combination lamp harness connector or the door mirror harness connector (if equipped with turn signal in mirror) in question.
3.Turn the ignition switch ON.
4.Operate the turn signal switch.
5.While the turn signal is operating, check the voltage between the front combination lamp harness connector and ground.










6.While the turn signal is operating, check the voltage between the rear combination lamp harness connector and ground.





7.While the turn signal is operating, check the voltage between the door mirror harness connector and ground.





Is the inspection result normal?
YES- GO TO 5.
NO- GO TO 3.

3. CHECK TURN SIGNAL LAMP CIRCUIT FOR OPEN

1.Turn the ignition switch OFF.
2.Disconnect BCM harness connector M19 or M20 in question.
3.Check continuity between the BCM harness connector M20 and the front combination lamp harness connector.





4.Check continuity between the BCM harness connector M19 and the rear combination lamp harness connector.





5.Check continuity between the BCM harness connector M20 and the door mirror harness connector in question.





Is the inspection results normal?
YES- GO TO 4.
NO- Repair or replace the harness or connectors.

4. CHECK TURN SIGNAL LAMP SHORT CIRCUIT

1.Check continuity between the BCM harness connector M19 or M20 and ground.





Are the inspection results normal?
YES- Replace BCM. Refer to "Removal and Installation" Service and Repair.
NO- Repair or replace the harness or connectors.

5. CHECK TURN SIGNAL LAMP GROUND CIRCUIT

1.Check continuity between the front combination lamp harness connector or the rear combination lamp harness connector or the door mirror harness connector in question and ground.





2.Check continuity between the rear combination lamp harness connector and ground.





3.Check continuity between the door mirror harness connector and ground.










Are the inspection results normal?
YES- Replace the malfunctioning lamp.
NO- Repair or replace the harness or connectors.