Turn Signals: Description and Operation
GF82.10-P-3008G Turn Signal Indicator Actuation, Function
MODEL 463.306 /336 /346 up to 31.5.12 as of model year 2011 /YoM 10
MODEL 463.202 /222 /236 /237 up to 31.5.12 as of model year 2009 /YoM 08
MODEL 463.247 /248 /249 /254 up to 31.8.08 as of model year 2007
MODEL 463.270 /271 /303 /340 /341 up to 31.5.12 as of model year 2007
1 Turn signaling request
2 Request for hazard flashing
3 Crash flashing request
4 Flasher frequency output
5 Turn signal light actuation
6 Flashing status indication
A1 Instrument cluster
A1e1 Left turn signal indicator lamp
A1e2 Right turn signal indicator lamp
E3e1 Left turn signal lamp
E4e1 Right turn signal lamp
E6/1 Left turn signal lamp
E6/2 Right turn signal lamp
E6/5 Left outside mirror turn signal lamp
E6/6 Right outside mirror turn signal lamp
N2/7 Restraint systems control unit
N10/1 Front signal acquisition and actuation module (SAM)
N10/2 Rear signal acquisition and actuation module (SAM)
N28/1 Trailer recognition control unit (with code (Q55) Trailer hitch with reinforced low ball head)
N69/1 Door control module front left
N69/2 Door control module front right
N72/1 Upper control panel control unit
N72/1s5 Hazard warning system switch
N80 Steering column tube module
S4 Combination switch
X58 Trailer hitch socket, 13-pin (with code (Q55) Trailer hitch with reinforced low ball head)
B Interior CAN
Turn signal actuation in general
The turn signal actuation can be triggered by different events. For this reason, the turn signal actuation is prioritized as follows:
1. Crash flashing, triggered by the restraint systems control unit
2. Flashing, triggered by the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) (for special-purpose vehicles)
3. Flashing (with code (FZ5) Anti-theft alarm system (ATA [EDW]) or (FZ8) Anti-theft alarm system with interior protection), triggered by rear SAM
4. Turn signaling, triggered by combination switch via the steering column tube module
5. Hazard warning flashers, triggered by the hazard warning system switch in the upper control panel control unit
6. Central locking open/close feedback, triggered by the EZS control unit (N73)
General turn signal actuation function sequence
The turn signal light actuation comprises several subfunctions:
^ Turn signals
^ One-touch turn signaling
^ Hazard warning flashing
Turn signals
Function requirements:
^ Circuit 15R ON
Operational sequence turn indicators
The position of the combination switch is recorded by the steering column tube module and forwarded to the rear SAM via the interior CAN (CAN B).
In its role as master control unit, the rear SAM forwards each request for all the turn signal functions via the interior CAN.
Left turn signal:
The front SAM actuates the left turn signal lamp.
The left front door control unit actuates the left outside mirror turn signal lamp.
The rear SAM actuates the left turn signal light in the left taillamp (E3).
Right turn signal:
The front SAM actuates the right turn signal lamp.
The right front door control unit actuates the right outside mirror turn signal lamp.
The rear SAM actuates the right turn signal light in the right taillamp (E4).
Flashing on trailer (with code (Q55) Trailer hitch with reinforced low ball head):
The trailer recognition control unit actuates the corresponding turn signal lights on the trailer via the trailer hitch socket (13-pin).
Feedback:
The instrument cluster receives the turn signal requests from the rear SAM via the interior CAN and actuates the left turn signal indicator lamp or the right turn signal indicator lamp.
The flashing frequency is f = 1.5 Hz with a light/dark duty cycle of 52 % to 48 %.
If a faulty turn signal light or turn signal lamp is detected, the frequencies of the turn signal indicator lamps in the instrument cluster double. The frequency of the turn signal lights and turn signal lamps remains at f = 1.5 Hz.
The turn signal procedure is ended following automatic reset when the vehicle is countersteered or through manual reset of the combination switch.
One-touch turn signaling
Function requirements:
^ Circuit 15R ON
Turn signal lamp touch control, function sequence
The operational sequence for the turn signal lamp touch control is the same, in relation to the signal flow, as that for the turn signal indicator. The difference lies in the triggering and ending of the turn signal procedure.
For one-touch turn signaling, the combination switch need only be pressed to the index point for t < 500 ms in the required turn signal direction
This initiates actuation of three turn signal cycles.
One-touch turn signaling is canceled by actuation of the hazard warning flashers, operation of the combination switch in the respective opposite direction as well as the central locking system open/close signal from the EZS control unit.
Hazard warning flashers
The hazard warning flashers can be actuated as follows:
^ Manual activation
^ Automatic activation in event of airbag deployment
Manual activation
Function requirements:
^ Circuit 30 ON
Manual activation function sequence
The hazard warning flasher is activated by pressing the hazard warning system switch.
The status of the hazard warning system switch is read in by the upper control panel control unit and forwarded to the rear SAM via the interior CAN.
The function sequence for the hazard warning flasher is identical to that for turn signaling in terms of signal flow. However, the turn signal lights and turn signal lamps on both sides of the vehicle are actuated.
The duty cycle is dependent on the position of the transmitter key (A8/1) in the EZS control unit:
^ Circuit 15R On: light 58 %, dark 42 %
^ Circuit 15R Off: light 35 %, dark 65 %
Feedback:
In addition to the turn signal indicator lamps in the instrument cluster, the indicator lamp in the hazard warning system switch is also actuated.
Automatic activation in event of airbag deployment
Function requirements
^ Airbag deployment
^ Deceleration a > 4 g
Function sequence for automatic activation in event of airbag deployment
In the event of an airbag deployment, the restraint systems control unit immediately sends a signal to the rear SAM for actuation of the turn signal lights and turn signal lamps.
This function is deactivated by pressing the hazard warning system switch.
