Turn Signals: Testing and Inspection

TURN SIGNAL LAMP CIRCUIT

Description

The BCM monitors inputs from the combination switch (high beam and turn signal 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.While operating the test items, check that the turn signal lamp blinks.

LH: Turn signal lamp LH blinking
RH: Turn signal lamp RH blinking
OFF: The turn signal lamp OFF

Does the turn signal lamp blink?
YES- Turn signal lamp circuit is normal.
NO- .


Diagnosis Procedure

Regarding Wiring Diagram information, [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 combination lamp connector and the rear combination lamp connector.
3.Turn the ignition switch ON.
4.With turn signal switch operating, check the voltage between the front combination lamp harness connector and ground.





5.With turn signal switch operating, check the voltage between the rear combination lamp harness connector and ground.





Is voltage reading as specified?
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 connector M20.
3.Check continuity between the BCM harness connector M20 and the front combination lamp connector.





4.Check continuity between the BCM harness connector M20 and the rear combination lamp connector.





Are continuity test results as specified?
YES- GO TO 4.
NO- Repair the harness or connector.

4. CHECK TURN SIGNAL LAMP SHORT CIRCUIT

Check continuity between the BCM harness connector M20 and ground.





Does continuity exist?
YES- Repair the harness or connector.
NO- Replace BCM. Service and Repair.

5. CHECK TURN SIGNAL LAMP GROUND CIRCUIT

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





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





Are continuity test results as specified?
YES- Replace the malfunctioning lamp.
NO- Repair the harness or connector.