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Home >> Mercedes Benz >> 2016 >> CLS400 4Matic >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 218 Chassis - 1 Of 5 >> Basic Knowledge >> Windshield wiper, function - GF82.30-P-3004FQ

Windshield wiper, function - GF82.30-P-3004FQ

MODEL 218 

Function requirements, general 

IMPORTANT The electronic ignition lock control unit (N73) sends status of circuit 15R over the interior CAN (CAN B) to the front SAM control unit with fuse and relay module (N10/1).

Wiping windshield, general 

The windshield wiping function keeps the windshield free of water, snow, etc.

The windshield wiper function is comprised of the following subfunctions:

Intermittent wipe function sequence 

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

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

The steering column tube module control unit (N80) reads in the switch position of the combination switch directly and sends this via chassis CAN (CAN E) (up to 28.2.13) or chassis CAN 1 (CAN E1) (as of 1.3.13) to the front SAM control unit. The front SAM control unit sends this over the wiper/inside rearview mirror-LIN (LIN 2) to the rain/light sensor. The rain/light sensor then calculates the required wipe frequency on the basis of the amount of windshield wetness and sends the relevant request back over the wiper/inside rear-view mirror LIN to the front SAM control unit. The front SAM control unit actuates the wiper motor (M6/1) via the wiper/inside rearview mirror LIN.

The intermittent wipe function is interrupted under the following conditions:

Touch wiping function sequence 

The touch wiping function can only be activated, if the multifunction switch is set to positions "0", "1" or "2". If the windshield wiper is not located in the rest position, the request of the combination switch is ignored. The touch wiping function is activated by pressing the multifunction switch up to the catch point.

Wipe once: To wipe once, briefly push the combination switch to the detent point.

Repeated wiping: If the multifunction switch is operated for an extended period of time in position "0", wiping is performed for the operating period, however, only for a maximum of t = 30 s.

The steering column tube module control unit reads in the switch position of the combination switch directly and sends this via chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) to the front SAM control unit. The front SAM control unit then actuates the wiper motor over the wiper/inside rearview mirror LIN accordingly.

IMPORTANT If the combination switch is pressed and held in the "0" position for longer than t = 30 s, the front SAM control unit judges this to be a "stuck combination switch" and interrupts the touch wiping function despite a pending request.

The speed at which the windshield wiper is moved during touch wiping, corresponds to the wiping speed in position "3" (continuous wipe at low speed).

The touch wiping function is interrupted under the following conditions:

Function sequence of wiping at specified speed 

The wipe function with predefined speed is activated by turning the multifunction switch to position "3" (continuous wipe at low speed) or position "4" (continuous wipe at high speed). The steering column tube module control unit reads in the switch position of the combination switch directly and sends this via chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) to the front SAM control unit. The front SAM control unit then actuates the wiper motor over the wiper/inside rearview mirror LIN accordingly.

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

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 

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 wipers remain in the park position despite an actuated manual or automatic wipe request. If a door is opened during wiping, the front SAM control unit interrupts the actuation of the wiper motor.

The following variables are considered here:

Vehicle speed:

The instrument cluster (A1) transmits the vehicle speed information to the front SAM control unit via the 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 this via chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) to the front SAM control unit.

Status of the front doors:

Opening of the left front door is detected by the status of the left front door rotary tumbler switch (A85s1) in the left front door lock (A85), which is read in by the left front door control unit (N69/1). Opening of the right front door is detected by the status of the right front door rotary tumbler switch (A85/1s1) in the right front door lock (A85/1), which is read in by the right front door control unit (N69/2). The respective front door control unit sends the corresponding status to the front SAM control unit over the interior CAN. 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:

IMPORTANT At circuit 15R ON no information on the current gear range is sent by the fully integrated transmission control unit (Y3/8n4) over the drive train CAN (CAN C), CDI control unit (N3/9) (with diesel engine) or ME-SFI [ME] control unit (N3/10) (with gasoline engine) and the chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13). Instead, "Gear range N" is constantly sent. The current gear range is only available as of circuit 15 On. The wiper startup suppression function is not canceled by circuit15R On through the status of the gear range.

Additional function requirements for wipe stop 

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 at a speed of 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 instrument cluster sends the vehicle speed to the front SAM control unit over the interior CAN. The steering column tube module control unit reads in the switch position of the combination switch directly and sends this via chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) to the front SAM control unit. The open engine hood is detected by the status of the left engine hood contact switch (S62/43). The rear SAM control unit with fuse and relay module (N10/2) reads in the status of the left engine hood contact switch directly and sends this over the interior CAN to the front SAM control unit. If an open engine hood is detected, the front SAM control unit interrupts the wiper motor actuation.

Additional function requirement for automatic speed reduction of the wiper system (without code (494) USA version) 

Function sequence for automatic speed reduction of wiper system (without 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 interior CAN. The steering column tube module control unit reads in the switch position of the combination switch directly and sends this via chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) to the front SAM control unit. The front SAM control unit reads in all relevant information, evaluates it and switches the wiper speed of the wiper motor back by one stage via the wiper/inside rearview mirror LIN.

The automatic speed reduction is canceled under the following conditions:

IMPORTANT Final wipe:

If the windshield wipers are not in the park position when the wipe function is switched off (discontinuation of function requirements), a final wipe is performed until the park position is reached.

Electrical function schematic for windshield wiper PE82.30-P-2051-97XAA
Overview of system components, wiper system (WSA) GF82.30-P-9997FQ 
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