Turn Signal Indicator Actuation, Function - GF82.10-P-3008RD

Model 172.4 up to model year 2017 

Function requirements, general 

• No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)

Turn signal light actuation, general 

The turn signal light actuation consists of all functions for output of the turn signal, various warnings and feedback. The master control unit for all turn signal functions is the front SAM control unit with fuse and relay module (N10/1). The front SAM control unit prioritizes all flashing requests and transmits a flasher frequency with a time period of the bright phase of the turn signal lamps over the interior CAN (CAN B) to the corresponding control units.

The turn signal light actuation function includes the following subfunctions:

• Function sequence for turn indicators 
• Function sequence, hazard warning flashing 

Additional function requirements for turn signaling 

• Circuit 15R ON

The electronic ignition lock control unit (N73) sends the status of circuit 15 to the front SAM control unit via interior CAN.

Function sequence for turn indicators 

The turn signaling function encompasses the following subfunctions:

• Function sequence, left turn signaling 
• Function sequence, right turn signaling 
• Function sequence, one-touch turn signaling 

Function sequence, left turn signaling 

The left turn signal function is requested by pushing the combination switch (S4) downward. The steering column tube module control unit (N80) directly reads in the position of the combination switch and transmits it to the front SAM control unit via the chassis CAN (CAN E). The front SAM control unit receives this, outputs the request for issuing the left turn signal function as a flasher frequency to the relevant control units via the interior CAN and actuates the left front turn signal light (E1e5) in the left front lamp unit (E1).

The left door control unit (N69/1) receives the flasher frequency and actuates the left outside mirror turn signal lamp (E6/5).

The rear SAM control unit with fuse and relay module (N10/2) receives the flasher frequency and actuates the left rear turn signal light (E3e1) in the left rear lamp unit (E3).

Function sequence, right turn signaling 

The right turn signal function is requested by pushing the combination switch upward. The steering column tube module control unit directly reads in the position of the combination switch and transmits it to the front SAM control unit via the chassis CAN. The front SAM control unit receives this, outputs the request for issuing the right turn signal function as a flasher frequency to the relevant control units via the interior CAN and actuates the right front turn signal light (E2e5) in the right front lamp unit (E2).

The right door control unit (N69/2) receives the flasher frequency and actuates the right outside mirror turn signal lamp (E6/6).

The rear SAM control unit receives the flasher frequency and actuates the right rear turn signal light (E4e1).

Function sequence, one-touch turn signaling 

With regard to signal flow, the function sequence of the touch turn signal function corresponds to that of the left turn signal and right turn signal functions. The difference is in the triggering and ending of the turn signal procedure. The combination switch must only be operated briefly (t < 440 ms) in the desired turn signal direction. Three flashing cycles are output by the front SAM control unit.

The one-touch turn signaling function is interrupted through actuation of the hazard warning flashing function or through actuation of the combination switch in the opposite direction.

The respective active function is displayed for the driver by means of actuating the left turn signal light indicator lamp (A1e1) or the right turn signal light indicator lamp (A1e2) and the acoustic turn signal light function check (A1h2). For this purpose, the instrument cluster (A1) receives the flasher frequency transmitted by the front SAM control unit via interior CAN.

If a turn signal light or turn signal lamp fails, the frequencies of the turn signal indicator lamps and the turn signal light function check in the instrument cluster double. The flashing frequency of the turn signal lights and turn signal lights of f = 1, 5 Hz continues to remain.

Substitute light control: If the left rear turn signal light fails, the outer left brake light and taillight (E3e11) is actuated as a substitute, and if the right rear turn signal light fails, the outer right brake light and taillight (E4e11) is actuated as a substitute.

Function sequence, hazard warning flashing 

The hazard warning flasher function sequence is the same as that for turn signaling with regard to the signal flow. However, all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously. In addition to the displays in the instrument cluster, the indicator lamp in the hazard warning system button (N72/1s5) in the UCP control unit (N72/1) is actuated by the front SAM control unit over the instrument panel LIN (LIN 1).

Depending on the status of circuit 15, two duty cycles are output by the front SAM control unit:

• With circuit 15R On: light 58 %, dark 42 %
• With circuit 15R Off: light 35 %, dark 65 %

The hazard warning flashing function encompasses the following subfunctions:

• Function sequence for hazard warning flashing, manual 
• Function sequence for hazard warning flashing for emergency braking 
• Function sequence for hazard warning flasher when airbag deployed 
• Function sequence for hazard warning flashing in the event of crash detection 
• Function sequence, feedback from locking/unlocking of central locking (CL) 
• Function sequence for anti-theft alarm system (ATA [EDW]) - Flashing (with CODE 551 (Anti-theft alarm system (ATA [EDW]))

Function sequence for hazard warning flashing, manual 

The manual hazard warning flasher function is activated by pressing the hazard warning system button. The front SAM control unit reads in the status of the hazard warning system button via the instrument panel LIN. Afterwards all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously.

Additional function requirements for hazard warning flashing for emergency braking 

• Circuit 15 On (transmitted by the electronic ignition lock control unit via the interior CAN)
• Emergency braking detected within t = 500 ms (vehicle speed v > 70 km/h and active Brake Assist System or vehicle deceleration a > 7.5 m/s ² )

Function sequence for hazard warning flashing for emergency braking 

In the event of emergency braking, the Electronic Stability Program control unit (N30/4) transmits an appropriate signal via the chassis CAN to the front SAM control unit.

If the vehicle is decelerated below the speed threshold of v = 3 km/h due to the emergency braking, the front SAM control unit activates the hazard warning flasher function by means of outputting the flasher frequency via the interior CAN. All turn signal lights and turn signal lamps are actuated at the same time on the vehicle.

The instrument cluster sends the vehicle speed to the front SAM control unit over the interior CAN.

This function is deactivated by pressing the hazard warning system button or upon exceeding a speed of v = 10 km/h.

Additional function requirements for hazard warning flasher when airbag deployed 

• Deceleration a > 4 g

Function sequence for hazard warning flasher when airbag deployed 

If an airbag is deployed, the supplemental restraint system control unit (N2/10) sends a corresponding signal via the chassis CAN to the front SAM control unit. The front SAM control unit then initiates the hazard warning flashing function by means of outputting the flasher frequency via interior CAN. All turn signal lights and turn signal lamps are actuated at the same time on the vehicle.

This function is deactivated by pressing the hazard warning system button or by globally unlocking the central locking.

Additional function requirements for hazard warning flashing for crash recognition 

• Vehicle deceleration a > 6 g

Function sequence for hazard warning flashing in the event of crash detection 

A crash sensor is integrated in the front SAM control unit. If this detects a crash event during a time-out error of the supplemental restraint system control unit (missing cyclically transmitted CAN messages), the front SAM control unit initiates the hazard warning flasher function by outputting the flasher frequency via the interior CAN. All turn signal lights and turn signal lamps are actuated at the same time on the vehicle.

This function is deactivated by pressing the hazard warning system button or by globally unlocking the central locking.

Function sequence, feedback from locking/unlocking of central locking (CL) 

When the central locking system is locked/unlocked, the electronic ignition lock control unit requests the hazard warning flashing function via the interior CAN. To this end, the electronic ignition lock control unit sends the status of the central locking over interior CAN to the front SAM control unit.

The front SAM control unit activates the hazard warning flashing function for one flasher cycle when the central locking system is unlocked, and for three flasher cycles when the central locking system is locked.

All vehicle doors must be closed in order to output the hazard warning flashing function.

The trunk lid is assessed as a vehicle door. Acoustic feedback also occurs in accordance with the flashing cycles by means of actuating the left horn (H2) and right horn (H2/1).

Information about the function sequence is described in detail in the "Theft protection and locking function description".

Function sequence for ATA [EDW] flashing (with code 551 (Anti-theft alarm system (ATA [EDW]))) 

When an ATA [EDW] alarm is triggered, the rear SAM control unit requests the hazard warning flashing function via interior CAN. The front SAM control unit generates a corresponding flasher frequency that is output via interior CAN. All turn signal lights and turn signal lamps are actuated at the same time on the vehicle.

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