Turn signal indicator actuation, function - GF82.10-P-3008FLM

MODEL 212 as of model year 2014 

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.

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). The instrument cluster receives the flasher frequency sent by the front SAM control unit via interior CAN for this. If a turn signal light or turn signal lamp fails, the frequency of the respective turn signal 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 lamps of f = 1.5 Hz remains unchanged.

The turn signal light actuation encompasses the following partial functions:

• 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 comprises the following subfunctions:

• Function sequence, left turn signal indicator 
• Function sequence for right turn signal indicator 
• Function sequence, touch turn signal indicator 

Function sequence, left turn signal indicator 

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

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

• Instrument cluster
• Rear SAM control unit with fuse and relay module (N10/2)
• Trailer recognition control unit (N28/1) (with code (550) Trailer hitch)
• Left front door control unit (N69/1)

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

On vehicles with code (640) SAE dynamic LED headlamp for right-hand traffic or code (641) Dynamic LED headlamp for left-hand traffic or code (642) Dynamic LED headlamp for right-hand traffic, 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 turn signal light, parking light, side marker lamp and daytime running light (E1e18) accordingly.

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

On vehicles with code (460) Canada version or code (494) USA version, the rear SAM control unit actuates the left brake light (E3e4) and the left taillight and brake light (E3e17).

The left front door control unit (N69/1) receives the flasher frequency and actuates the left outside mirror turn signal lamp (E6/5) in the left outside mirror (M21/1).

On vehicles with code (550) Trailer hitch, the trailer recognition control unit receives the flasher frequency and actuates the left turn signal light on the trailer via the trailer socket (X58).

Function sequence for right turn signal indicator 

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 outputs the "Right turn signal" (flasher frequency) request via interior CAN to the following control units:

• Instrument cluster
• Rear SAM control unit
• Trailer recognition control unit (with code (550) Trailer hitch)
• Right front door control unit (N69/2)

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

On vehicles with code (640) SAE dynamic LED headlamp for right-hand traffic or code (641) Dynamic LED headlamp for left-hand traffic or code (642) Dynamic LED headlamp for right-hand traffic, the front SAM control unit sends the flasher frequency via chassis CAN 2 to the right headlamp control unit (E2n9), which actuates the right turn signal light, parking light, side marker lamp and daytime running light (E2e18) accordingly.

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

On vehicles with code (460) Canada version or code (494) USA version, the rear SAM control unit actuates the right brake light (E4e4) and the right taillight and brake light (E4e17).

The right front door control unit (N69/2) receives the flasher frequency and actuates the right outside mirror turn signal lamp (E6/6) in the right outside mirror (M21/2).

The trailer recognition control unit receives the flasher frequency and actuates the right turn signal light on the trailer via the trailer socket.

Function sequence, touch turn signal indicator 

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.

Substitute lamp actuation on vehicles without code (460) Canada version and without code (494) USA version:

If the left rear turn signal light fails, the left brake light is actuated as a substitute and if the right rear turn signal light fails, the right brake light is actuated as a substitute.

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.

In addition to the indicator lamps in the instrument cluster, the indicator lamp in the hazard warning system button (N72/1s5) in the upper control panel control unit (N72/1) is actuated by the front SAM control unit via 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 %

If the failure of a turn signal light or a turn signal lamp is detected during hazard warning flashing, the frequency of the turn signal light indicator lamps and the turn signal light function check does not double.

The hazard warning flasher function comprises the following subfunctions:

• Function sequence for hazard warning flashing, manual 
• Function sequence, hazard warning flashing after emergency braking 
• Function sequence for hazard warning flashing for airbag deployment 
• Function sequence for hazard warning flashing in the event of crash detection 
• Function sequence, feedback from locking/unlocking of central locking (CL) 
• Function sequence, antitheft alarm system (ATA) flashing (with code (551) Antitheft alarm system (ATA)) 

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 instrument panel LIN and activates the hazard warning flasher function by means of outputting the flasher frequency via interior CAN. Afterwards all the turn signal lights and turn signal lamps on the vehicle are actuated synchronously.

Additional function requirements, hazard warning flashing after 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 Brake Assist System active or vehicle deceleration a > 7.5 m/s² )

Function sequence, hazard warning flashing after emergency braking 

In the event of emergency braking, the Electronic Stability Program control unit (N30/4) (model 212 (except 212.074/092/095/098/274/292/298) without code (233) DISTRONIC PLUS), the regenerative braking system control unit (N30/6) (model 212.095/098/298) or the Premium Electronic Stability Program control unit (N30/7) (model 212 (except 212.095/098/298) with code (233) DISTRONIC PLUS, model 212.074/092/274/292) sends a corresponding signal via chassis CAN 1 to the front SAM control unit.

If the vehicle was then decelerated below the speed of v = 3 km/h, the front SAM control unit activates the hazard warning flasher function by outputting the flasher frequency via interior CAN. Afterwards all the turn signal lights and 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 flashing for airbag deployment 

• Deceleration a > 4 g

Function sequence for hazard warning flashing for airbag deployment 

If an airbag is triggered, the supplemental restraint system control unit (N2/10) sends the crash signal 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.

Additional function requirements for hazard warning flashing for crash recognition 

• Deceleration a > 6 g

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

A crash sensor is integrated into the front SAM control unit. If this detects a crash event during a time-out of the supplemental restraint system control unit, the front SAM control unit activates the hazard warning flasher function by outputting the flasher frequency via 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.

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 the turn signal lamps on the vehicle are actuated synchronously.

All vehicle doors must be closed in order to output the hazard warning flashing function. The trunk lid (model 212.0/1) or the liftgate (model 212.2) is considered a vehicle door.

In accordance with the flashing cycles, when locking the CL [ZV] with the "Acoustic locking feedback" function activated the left horn (H2) and right horn (H2/1) are also actuated.

Function sequence for ATA 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.

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

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