Windshield Wiper, Function - GF82.30-P-3004FR

Model 257, 290 

up to model year 2021 

Function requirements, general 

• Circuit 15R On:

  The electronic ignition lock control unit (N73) sends the status of circuit 15 via interior CAN (CAN B) to the front SAM control unit (N10/6).

Wiping windshield, general 

The windshield wiper function is comprised of the following subfunctions:

• Intermittent wipe function sequence 
• Single wipe function sequence 
• Function sequence of wiping at specified speed 
• Function sequence for interrupting wiping during engine start 
• Wiper start suppression function sequence 
• Function sequence for wipe stop 
• Function sequence for automatic speed reduction of windshield wiper system (except CODE 494 (USA version)) 

Intermittent wipe function sequence 

The intermittent wipe function is activated by turning the combination switch (S4) to switch position "1" (rain sensor (B38/2b1) in the rain/light sensor with additional functions (B38/2) low sensitivity) or to switch position "2" (rain sensor high sensitivity).

When the system is switched from switch position "0" to switch position "1" or "2", there is an automatic wipe cycle, the so-called "Reaction wipe".

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 the chassis FlexRay (Flex E), electronic ignition lock control unit and interior CAN.

The front SAM control unit sends the wipe sensitivity via rain/light sensor LIN (LIN B16) to the rain/light sensor with additional functions.

The rain/light sensor with additional functions uses the wipe sensitivity and the amount of windshield wetness as a basis for calculating the frequency of required wipe procedures, and then sends the corresponding wipe request back over the rain/light sensor LIN to the SAM control unit. The front SAM control unit then actuates the wiper motor (M6/1) over the rain/light sensor LIN correspondingly.

The wetness of the windshield is detected by the rain sensor in the rain/light sensor with additional functions. The rain/light sensor with additional functions reads in the signals from the rain sensor directly and evaluates them.

The intermittent wipe function is interrupted under the following conditions:

• Activating wipe/stop function
• Activating wash function
• Activating single wipe function
• Activation of afterwipe function
• Activating wiper startup suppression function
• Turning combination switch to switch position "0", "3" or "4"
• Blocking of wiper motor
• Missing or faulty rain sensor data

Additional function requirements for single wipe 

• Combination switch in switch position "0", "1" or "2"

The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit.

Single wipe function sequence 

The single wipe function is activated by briefly pressing the multifunction switch up to the catch point. If the combination switch is pressed for longer, wiping takes place in accordance with the duration for which it is pressed, but only for a maximum of t = 30 s.

The front SAM control unit actuates the wiper motor over the rain/light sensor LIN accordingly. If the windshield wiper is not located in the rest position, the request of the combination switch is ignored.

If the combination switch is pressed in the "0" switch position and held down for longer than t = 30 s, the SAM control unit evaluates this as a "stuck combination switch" and aborts actuation despite the pending request.

The speed at which the windshield wipers are moved corresponds to the wiping speed in switch position "3" (continuous wipe at low speed).

The single wipe function is interrupted under the following conditions:

• Activating wash function
• Activation of afterwipe function
• Activating wipe interruption during engine start function
• Blocking of wiper motor

Function sequence of wiping at specified speed 

The wipe function with predefined speed is activated by turning the combination switch to switch position "3" (continuous wipe at slow speed) or switch position "4" (continuous wipe at fast speed). The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit. The front SAM control unit then actuates the wiper motor over the rain/light sensor LIN correspondingly.

The wash function with predefined speed is interrupted under the following conditions:

• Activating wipe/stop function
• Activating wash function
• Activation of afterwipe function
• Activation of speed reduction function (except CODE 494 (USA version))
• Turning combination switch to switch position "0", "1" or "2"
• Blocking of wiper motor

Function sequence for interrupting wiping during engine start 

During engine start, the front SAM control inhibits the actuation of the wiper motor. Any wiping procedure already started is terminated. The engine start is recognized by the transmission of the status of circuit 50. The electronic ignition lock control unit transmits the status of circuit 50 to the front SAM control unit via the interior CAN.

Additional function requirements for wiper start suppression 

• Vehicle speed v < 3 km/h
• Combination switch in switch position "1" or "2"
• Rain sensor has detected a wet windshield

Wiper start suppression function sequence 

The wiper startup suppression is intended to prevent people from being sprayed with water from the windshield when getting in or out of the vehicle as the result of an initiated wipe operation. The windshield wipers remain in the park position despite a wipe request triggered manually or automatically. If a front door is opened during wiping, the front SAM control unit interrupts the actuation of the wiper motor.

To do this, the following variables are taken into account:

• Vehicle speed
• Switch position of the combination switch
• Wetting of the windshield
• Status of the front doors

Vehicle speed:

The instrument cluster (A1) sends the vehicle speed to the front SAM control unit over the user interface CAN (CAN HMI), electronic ignition lock control unit and interior CAN.

Switch position of the combination switch:

The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit.

Wetting of the windshield:

The wetness of the windshield is detected by the rain sensor in the rain/light sensor with additional functions. The rain/light sensor with additional functions reads in the signals of the rain sensor directly and sends the corresponding wipe request over the rain/light sensor LIN (LIN) to the front SAM control unit.

Status of the front doors:

The left front door control unit (N69/1) transmits the status of the left front door via the interior CAN to the front SAM control unit. The right front door control unit (N69/2) transmits the status of the right front door via the interior CAN to the front SAM control unit.

The front SAM control unit reads in all relevant information, evaluates it and interrupts actuation of the wiper motor. An already started wiping procedure is not interrupted immediately. The wipers continue to move to the park position.

The wiper start suppression is deactivated under the following circumstances:

• Vehicle speed: v ≥ 3 km/h
• Combination switch in switch position "3" or "4"
• Single wipe or wash function activated
• Driver and front passenger door closed and gear range "D" or "R" engaged (transmission 725):

  The fully integrated transmission control electric controller unit control unit (Y3/8n4) sends information on the current drive range over the drive CAN (CAN C1), powertrain control unit (N127), suspension FlexRay, electronic ignition lock control unit and the interior CAN to the front SAM control unit.

• Change from circuit 15C to circuit 15R

For circuit 15R ON, the fully integrated transmission control electric controller unit control unit does not send any information on the current drive range, but constantly sends drive range "N". The current gear range is only available as of circuit 15 On. The wiper startup suppression function is not canceled by circuit 15R On through the status of the gear range.

Additional function requirements for wipe stop 

• Wipe or wash function activated
• Vehicle speed v < 3 km/h

The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit. The instrument cluster sends the vehicle speed to the front SAM control unit over the user interface CAN (CAN HMI), electronic ignition lock control unit and interior CAN.

Function sequence for wipe stop 

The wipe stop function prevents the wiper motor from being actuated by the front SAM control unit when the engine hood is open and thus causing damage to the vehicle. If the engine hood is opened while driving (v < 3 km/h), the front SAM control unit immediately stops the wiper motor actuation.

At a speed of v > 6 km/h, the wiper stop function is deactivated, i.e. the wiper motor is actuated again from this speed onwards.

The opened hood is detected by the status of the front passenger engine hood contact switch (S62/42) and the driver side engine hood contact switch (S62/43). The front SAM control unit reads in the status of the front passenger side engine hood contact switch and the driver side hood contact switch directly.

Additional function requirement for automatic speed reduction of windshield wiper system (except CODE 494 (USA version)) 

• Combination switch in switch position "3" or "4"

The steering column tube module control unit reads in the switch position of the combination switch directly and sends it via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit.

Function sequence for automatic speed reduction of windshield wiper system (except CODE 494 (USA version)) 

It is assumed that the windshield does not become as wet at slow speeds. For this reason, the front SAM control unit reduces the wiper speed as soon as vehicle deceleration from v > 6 km/h to v < 3 km/h is detected.

The instrument cluster sends the vehicle speed to the front SAM control unit over the user interface CAN (CAN HMI), electronic ignition lock control unit and interior CAN.

The automatic speed reduction function of the windshield wiper system is interrupted under the following conditions:

• Vehicle speed v > 6 km/h
• Changing wiper speed
• Activating single wipe function
• Activating wash function

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