Windshield Washer, Function - GF82.35-P-3002RD

Model 172.4 

Function requirements, general 

• Circuit 15R ON

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

Washing windshield, general 

The windshield is kept clean by washing the windshield.

The windshield wash function is comprised of the following subfunctions:

• Washing function sequence 
• Afterwiping function sequence 
• Function sequence for interrupting washing during engine start 
• Function sequence for wash stop (with CODE 551 (Anti-theft alarm system (ATA [EDW])) 

Washing function sequence 

The washing function is activated by pressing the combination switch (S4) in axial direction beyond the detent point.

The steering column tube module control unit (N80) reads in the switch position of the combination switch and sends it via chassis CAN 1 (CAN E1) as of 01.03.2016 and via chassis CAN (CAN E) up to 29.02.2016 to the front SAM control unit.

The front SAM control unit receives the request and actuates the windshield washer system pump (M5/1).

During washing, wiping takes place with the wiper speed set on the combination switch.

When the combination switch is in the rest position, wiping takes place with speed "3".

The washing function is interrupted under the following conditions or after t = 15 s:

• Activation of the washer interruption function when the engine starts
• Activating wipe/stop function
• "Combination switch stuck" detection

When erroneous bit "Wpr_Flt" is active, i.e. windshield wiper defective, washing is not possible.

Afterwiping function sequence 

The afterwiping function is activated as soon as the combination switch is no longer activated. The steering column tube module control unit directly reads in the switch position of the combination switch and sends it via chassis CAN 1 as of 01.03.2016 and via chassis CAN up to 29.02.2016 to the front SAM control unit. The front SAM control unit then actuates the wiper motor (M6/1) through the wiper/inside rearview mirror LIN (LIN 2).

The number of afterwipe cycles depends on the combination switch actuation time:

• Actuation time t < 200 ms: Afterwiping does not take place.
• Actuation time t < 1 s: A single afterwipe occurs.
• Actuation time t > 1 s: Three afterwipes occur.

The front SAM control unit sends the status "Afterwipe active" via the wiper/inside rearview mirror LIN to the rain/light sensor (B38/2) (with code 345 (Windshield wiper with rain sensor). Wiping requests from the rain/light sensor during afterwiping are ignored.

Afterwiping takes place with the wiper speed set on the combination switch.

When the combination switch is in the rest position, afterwiping takes place with speed "3".

The afterwiping function is interrupted or aborted under the following conditions:

• Activation of the washer interruption function when the engine starts
• Wiper motor blockage detection
• Activating wash function
• Activating wipe/stop function

Function sequence for interrupting washing during engine start 

When the engine starts, the front SAM control unit blocks the actuation of the windshield washer system pump.

Any wiping procedure that has 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.

Function sequence for wash stop (with CODE 551 (Anti-theft alarm system (ATA [EDW])) 

If an open engine hood is detected via the pedestrian protection Hall sensor + engine hood ATA [EDW] switch (A38/1) (with code U60 (Active engine hood (pedestrian protection)) up to 31.05.2015) or the left engine hood contact switch (S62/43) (as of 01.06.2015 or except code U60 (Active engine hood (pedestrian protection)) up to 31.05.2015), the front SAM control unit interrupts the actuation of the windshield washer system pump.

If the engine hood is closed, the windshield washer system pump can be actuated again.

This is also possible if the engine hood is open and the vehicle speed exceeds v > 8 km/h.

The instrument cluster (A1) sends the vehicle speed via chassis CAN 2 (CAN E2) as of 01.03.2016 and via interior CAN up to 29.02.2016 to the front SAM control unit.

The status of the pedestrian protection Hall sensor + engine hood ATA [EDW] switch (up to 31.05.2015) or the left engine hood contact switch is read in directly by the rear SAM control unit with fuse and relay module (N10/2) and sent via interior CAN to the front SAM control unit.

	Electrical function schematic for windshield washer		PE82.35-P-2051-97TAA
	Overview of system components for windshield wiper system		GF82.30-P-9996RD