Turn Signals: Description and Operation
GF82.10-P-3008MCU Turn Signal Indicator Actuation, Function
1 Turn signaling request
2 Request for hazard flashing
3 Actuation of turn signal control indicator
4 Crash signal
5 Vehicle speed signal
6 Actuation of turn signal
A1 Instrument cluster
A1e1 Left turn signal indicator lamp
A1e2 Right turn signal indicator lam
E1e5 Left turn signal light
E2e5 Right turn signal light
E3e11 Left brake/turn signal light
E4e11 Right brake/turn signal light
E22/1 Left additional turn signal lamp
E22/2 Right additional turn signal lamp
K52/11 Left turn signal/stop lamp relay
K52/12 Right turn signal/stop lamp relay
N2/7 Restraint systems control unit
N10/10 SAM control unit
N47-5 ESP control unit
S4 Combination switch
S6/1 Cockpit switch group
S6/1s1 Hazard warning switch
CAN Controller Area Network (data bus/CAN bus) (CAN)
Functions
^ Turn signals
^ One-touch turn signaling
^ Hazard warning flashing
Turn signaling and one-touch turn signaling
Function requirements:
^ Circ. 15 ON
Turn signals
Turn signaling is requested by pushing the combination switch down or up past the actuation point.
The SAM control unit registers the respective position of the combination switch and actuates the following lamps:
^ Left turn signal light in left front lamp unit (E1)
^ Left brake light/turn signal light in left taillamp (E3)
^ Left additional turn signal lamp
or
^ Right turn signal light in right front lamp unit (E2)
^ Right brake light/turn signal light in right taillamp (E4)
^ Right additional turn signal lamp
Stop turn signaling
Turn signaling is stopped by means of countersteering (automatic return of switch), manually returning the combination switch or activating the hazard warning flasher function.
One-touch turn signaling
During one-touch turn signaling the combination switch is only briefly moved to the required signaling position. If the turn combination switch is not engaged into place in the signaling position, a sequence of three turn-signal cycles is triggered.
The SAM control unit registers the respective position of the combination switch and actuates the following lamps:
^ Left turn signal light in left front lamp unit
^ Left brake light/turn signal light in left taillamp
^ Left additional turn signal lamp
or
^ Right turn signal light in right front lamp unit
^ Right brake light/turn signal light in right taillamp
^ Right additional turn signal lamp
One-touch turn signaling is stopped by activating the hazard warning flasher function.
Turn signaling and one-touch turn signaling feedback
The activated function is signaled to the instrument cluster by the SAM control unit via the CAN. The instrument cluster actuates the relevant turn signal indicator lamp as visual feedback. Acoustic feedback is also output on the speaker in the instrument cluster in the form of a turn signal sound indicator.
If one of the turn signal lamps fails, the flashing frequency of the indicator lamps, the flashing frequency of the other turn signal lamps and the frequency of the turn signal sound indicator is doubled.
Activating the hazard warning flasher using the hazard warning flasher switch
The status of the hazard warning flasher switch is registered by the SAM control unit, which actuates the turn signal lamps in the front lamp units, the brake lights/turn signal lights in the taillamps and the additional turn signal lamps.
Hazard warning flasher actuation as a result of rapid deceleration
If the vehicle is braked from a speed of more than 35 mph to a standstill, the hazard warning system is automatically activated. The current speed is determined by the ESP control unit and relayed via the CAN to the SAM control unit, which activates the hazard warning flasher function.
The hazard warning flasher function is deactivated automatically after starting off as soon as the vehicle speed reaches 6 mph, or manually using the hazard warning flasher switch.
Hazard warning flasher in event of crash
In the event of a crash the request is transmitted by the restraint systems control unit via the CAN to the SAM control unit, which activates the hazard warning flasher function. The hazard warning flasher function is switched off by operating the hazard warning flasher switch in the cockpit switch group.
In the event of a crash, the doors are also unlocked and the fuel pump with fuel level sensor (M3/3) is switched off.
Hazard warning flasher feedback
Visual feedback of the active hazard warning flasher function is provided by the indicator lamp in the hazard warning flasher switch and the indicator lamps in the instrument cluster, which are only active if circuit 15 is on, however. Acoustic feedback is also output on the speaker in the instrument cluster in the form of a turn signal sound indicator.
If one of the turn signal lamps fails, the flashing frequency of the turn signal indicator lamps, the flashing frequency of the other turn signal lamps and the frequency of the turn signal sound indicator do not change.
