System Operation

Turn Signal and Hazard Lamps

System Operation

System Diagram





Network Message Chart

DDM (Driver Door Module) Network Input Messages





Passenger Door Module (PDM) Network Input Messages






Turn Signals

The SASM (Steering Angle Sensor Module) monitors the multifunction switch position. When the multifunction switch is in the left or right TURN position, the SASM (Steering Angle Sensor Module) sends a turn signal switch status message over the LIN (Local Interconnect Network) circuit to the BCM (Body Control Module) indicating a request for the left or right turn signal.

When the BCM (Body Control Module) receives a request for a turn signal, the BCM (Body Control Module) supplies on/off voltage to the appropriate turn lamps. On vehicles equipped with door modules (window one-touch up), the BCM (Body Control Module) sends a turn indicator command message to the door modules over the communication network for the mirror turn lamps.

The timed on/off cycle for turn lamps is determined by the BCM (Body Control Module) and is set to flash approximately 70 times per minute if both the front and rear turn signal lamps operate correctly. If a front or rear turn signal lamp is inoperative, the BCM (Body Control Module) fast flashes the remaining turn lamp(s) approximately 150 times per minute to indicate a bulb outage to the driver.

The multifunction switch is a momentary contact switch, with 2 detents for the left turn position and 2 detents for the right turn position. When placed in the first detent and released, the corresponding turn signals flash 3 times and turn off. When the multifunction switch is moved to the second detent, the turn signal flashes until the steering wheel is turned in the opposite direction to mechanically return the multifunction switch to the rest position.

The BCM (Body Control Module) also provides an overload protection of the turn lamp output circuits. REFER to Field Effect Transistor (FET) Protection .

Hazard Lamps

The BCM (Body Control Module) sends a voltage signal to the hazard flasher lamp switch (on vehicles equipped with base or premium audio systems, this is integrated into the FCIM (Front Controls Interface Module)) to monitor for a hazard lamp function request. When the hazard flasher lamp switch is pressed, the voltage signal is routed to ground, indicating a request to activate or deactivate the hazard lamp function.

When the BCM (Body Control Module) receives a request for the hazard lamps, the BCM (Body Control Module) supplies on/off voltage to all the turn lamps.

The timed on/off cycle for the hazard lamps is approximately 70 times per minute, regardless of bulb outage.