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

Model 172.4 as of model year 2017 

Function requirements for turn signal light actuation, general 

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.

IMPORTANT Each active function is displayed to the driver by actuating the left turn signal indicator lamp (A1e1) or the right turn signal light indicator lamp (A1e2) and the audible turn signal light function check (A1h2) in the instrument cluster (A1). To this end, the instrument cluster receives the flasher frequency sent by the front SAM control unit over the interior CAN. If a turn signal light or turn signal lamp fails, the frequency of the respective turn signal light indicator lamp and the acoustic turn signal light function check in the instrument cluster doubles to f = 3 Hz. The flashing frequency of the turn signal lights and turn signal lights of f = 1, 5 Hz continues to remain.

The turn signal light actuation encompasses the following partial functions:

Additional function requirements for turn signaling 

IMPORTANT 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 comprises the following subfunctions:

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) reads in the switch position of the combination switch directly and sends this via chassis CAN 1 (CAN E1) to the front SAM control unit.

The front SAM control unit receives the switch position of the combination switch and sends the "Left turn signal" (flasher frequency) over the interior CAN to the following control units:

In vehicles without code 640 (High-performance LED) and without code 641 (Dynamic left-hand traffic LED headlamp) and without code 642 (Dynamic right-hand traffic LED headlamp), the front SAM control unit directly actuates the left front turn signal light (E1e5) in the left front lamp unit (E1).

In vehicles with code 640 (High-performance LED) or code 641 (Dynamic left-hand traffic LED headlamp) or code 642 (Dynamic right-hand traffic LED headlamp), the front SAM control unit sends the flasher frequency via chassis CAN 2 (CAN E2) to the left headlamp control unit (E1n9), which actuates the left position light, daytime running light and turn signal light (E1e25) accordingly.

The rear SAM control unit receives the flasher frequency and actuates the left rear turn signal light (E3e1) in the left rear lamp unit (E3) in vehicles without code 460 (Canada version) and without code 494 (USA version).

In vehicles with code 460 (Canada version) or code 494 (USA version), the rear SAM control unit actuates the following lamps:

The left door control unit receives the flasher frequency and actuates the left outside mirror turn signal lamp (E6/5) in the left outside mirror (M21/1).

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 switch position of the combination switch and sends it to the front SAM control unit via chassis CAN 1.

The front SAM control unit receives the switch position of the combination switch and sends the "Right turn signal" request (flasher frequency) over the interior CAN to the following control units:

In vehicles without code 640 (High-performance LED) and without code 641 (Dynamic left-hand traffic LED headlamp) and without code 642 (Dynamic right-hand traffic LED headlamp), the front SAM control unit directly actuates the right front turn signal light (E2e5) in the right front lamp unit (E2).

In vehicles with code 640 (High-performance LED) or code 641 (Dynamic left-hand traffic LED headlamp) or code 642 (Dynamic right-hand traffic LED headlamp), the front SAM control unit sends the flasher frequency via chassis CAN 2 (CAN E2) to the right headlamp control unit (E2n9), which actuates the right position light, daytime running light and turn signal light (E2e25) accordingly.

The rear SAM control unit receives the flasher frequency and in vehicles without code 460 (Canada version) and without code 494 (USA version), it actuates the right rear turn signal light (E4e1) in the right rear lamp unit (E4).

In vehicles with code 460 (Canada version) or code 494 (USA version), the rear SAM control unit actuates the following lamps:

The right door control unit receives the flasher frequency and actuates the right outside mirror turn signal lamp (E6/6) in the right outside mirror (M21/2).

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. To trigger the touch turn signaling function, the combination switch must only be pressed briefly (t < 440 ms) in the desired turn signal direction. Three flashing cycles are then output by the front SAM control unit.

The touch turn signaling function is interrupted by means of actuation of the hazard warning flasher function or activation of the combination switch in the opposite direction.

Function sequence, hazard warning flashing 

The function sequence for the hazard warning flasher is identical to that for turn signaling in terms of signal flow. However, all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously.

Along with the indicator lamps 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:

The hazard warning flasher function comprises the following subfunctions:

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 over the instrument panel LIN and activates the hazard warning flasher function by issuing a flasher frequency over the interior CAN. Afterwards all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously.

Additional function requirements for hazard warning flasher after emergency braking 

Function sequence for hazard warning flasher after emergency braking 

In the event of emergency braking, the Electronic Stability Program control unit (N30/4) sends a corresponding signal via chassis CAN 1 to the front SAM control unit. If the vehicle was 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 issuing the flasher frequency via interior CAN. All turn signal lights and the turn signal lamps on the vehicle are actuated synchronously.

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 exceeding a speed of v = 10 km/h.

Additional function requirements for hazard warning flasher when airbag deployed 

Function sequence for hazard warning flasher when airbag deployed 

If the airbag is deployed, the crash signal is transmitted by the supplemental restraint system (N2/10) control unit via chassis CAN 1 to the front SAM control unit. The front SAM control unit then actuates the hazard warning flashing function by means of outputting the flasher frequency over the interior CAN. Afterwards all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously.

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

Additional function requirements for hazard warning flashing for crash recognition 

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 timeout error of the supplemental restraint system control unit, the front SAM control unit activates the hazard warning flasher function by issuing the flasher frequency via the interior CAN. This serves to avoid any inadvertent activation of the local crash sensor.

Afterwards all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously.

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

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 turn signal lights and turn signal lamps are actuated at the same time on the vehicle.

IMPORTANT All vehicle doors must be closed in order to output the hazard warning flashing function. The trunk lid is assessed as a vehicle door.

Function sequence for ATA [EDW] flashing (with CODE 551 (Antitheft alarm system (ATA [EDW]))) 

If an ATA [EDW] alarm is triggered, the rear SAM control unit requests the hazard warning flasher function over the interior CAN. This request must be sent cyclically so that the flasher frequency results from the bright time and the cycle time.

The front SAM control unit receives this request, and then generates a corresponding flasher frequency which is sent over the interior CAN. All turn signal lights and the turn signal lamps on the vehicle are actuated synchronously.

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