Turn Signals: Testing and Inspection

TURN SIGNAL LAMP CIRCUIT





Description
The BCM monitors inputs from the combination switch (lighting 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-III
1. Select "FLASHER" of BCM (FLASHER) active test item.
2. With operating the test items, check that the turn signal lamp blinks.






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




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 connectors 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 and the front combination lamps harness connector.





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





Are continuity results as specified?
YES - GO TO 4
NO - Repair the harnesses or connectors.
4.CHECK TURN SIGNAL LAMP SHORT CIRCUIT





Check continuity between the BCM harness connector M20 and ground.





Does continuity exist?
YES - Repair the harnesses or connectors.
NO - Replace BCM. Service and Repair.
5.CHECK TURN SIGNAL LAMP GROUND CIRCUIT
1. Check continuity between the front combination lamp harness connectors and ground.










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





Are continuity results as specified?
YES - Replace the malfunctioning lamp.
NO - Repair the harnesses or connectors.