GF82.30-P-2200FL Rear Window Wiper System, Function

GF82.30-P-2200FL Rear Window Wiper System, Function

MODEL 212.2

Function requirements, general
- Circuit 15R ON

The electronic ignition switch control unit (N73) transmits circuit 15 status to the front SAM control unit with fuse and relay module (N10/1) via the interior CAN (CAN B). The front SAM control unit is the master control unit for the rear window wiper system function.

Rear window wiper system in general
The wiper system allows wiping and washing the rear window. The control logic for the rear window wiper system is stored in the front SAM control unit.

The rear window wiper system function is comprised of the following subfunctions:
- Function sequence for intermittent wipe on rear window
- Function sequence for backup wiping
- Function sequence for rear window washing
- Function sequence for rear window afterwipe
- Function sequence for rear window wiper startup suppression
- Function sequence for final wipe

Function sequence for intermittent wipe on rear window
The rear window intermittent wipe function is activated by actuating the 2nd ring on the multifunction switch (S4).
The steering column tube module control unit (N80) directly reads in the position of the combination switch and transmits it to the front SAM control unit via the chassis CAN (CAN E).
The front SAM control unit receives evaluates the switch position and transmits the "Rear window intermittent wipe" request to rear SAM control unit with fuse and relay module (N10/2) via the interior CAN. The rear SAM control unit then actuates the liftgate wiper motor (M6/4).
The actuation time is approx. t = 2 s (duration of wipe cycle). This is then followed by a delay of approx. t = 5 s. The activated rear window intermittent wipe function is confirmed by an illuminated symbol in the instrument cluster (A1). The front SAM control unit then transmits the "Active rear window intermittent wipe" status to the instrument cluster via the interior CAN.

Additional function requirements for backup wiping
- Windshield intermittent wipe function activated

Function sequence for backup wiping
When the windshield intermittent wipe function is activated, the backup wipe function is activated automatically when the vehicle is shifted into reverse gear

The liftgate wiper motor is actuated when the multifunction switch is set to the corresponding position:
- For interval 1 or interval 2:
The rear window wiper runs synchronously with the windshield wiper.

- With continuous wipe 1 or continuous wipe 2:
The rear window wiper wipes in continuous wiping mode, but not synchronously with the front windshield wiper.

- When the rain/light sensor (B38/2) is active, the rear window wiper operates with the wipe request activated by the rain/light sensor.

The steering column tube module control unit directly reads in the position of the combination switch and transmits it to the front SAM control unit via the chassis CAN.

The vehicle is shifted into reserve as follows:
Transmission 711, 716:
Shifting into reverse gear is defined by the status of the backup lamp switch (S16/2), which is read in directly by the front SAM control unit.

Transmission 722:
Shifting into reverse gear is defined by the selector lever position. The electronic selector lever module control unit (N15/5) (transmission 722.6) or the intelligent servo module for DIRECT SELECT (A80) (transmission 722.9) sends the selector lever position 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 to the front SAM control unit.

The front SAM control unit evaluates all of the relevant information and transmits an appropriate requests via the interior CAN to the rear SAM control unit. The rear SAM control unit actuates the liftgate wiper motor accordingly.

Additional function requirements, rear window washing
- Windshield wash not active

Function sequence for rear window washing
By actuating the 2nd ring on the combination switch, the rear window wash function is activated.
The steering column tube module control unit directly reads in the position of the combination switch and transmits it to the front SAM control unit via the chassis CAN. The front SAM control unit receives this and then actuates the windshield washer system pump (M5/1) in the opposite direction to the "windshield wash" function. Simultaneously the front SAM control unit transmits the request "Switch on rear window" to the rear SAM control unit via the interior CAN. The rear window wiper motor is then actuated directly by the rear SAM control unit.

The windshield washer system pump is actuated as long the "Rear window wash function" is requested by the multifunction switch.

After the "rear window wash" function has been activated, the rear window wiper motor starts to wipe in continuous mode after a short delay.

In order to prevent situations where the windshield washer system pump cannot be switched off because the combination switch is stuck, washing is aborted after a maximum of t = 15 s. The time and function are restarted after renewed actuation.

Function sequence for rear window afterwipe
After the rear window wash function is completed, i.e. the windshield washer system pump is no longer actuated and the running wash cycle is terminated, the rear window afterwipe function is activated. This is then followed by two afterwipe cycles in continuous mode.

If the time for the request of the rear window wash function is less than the time for the delayed actuation of the rear window wiper motor, only one afterwipe cycle is performed.

Additional function requirements for rear window wiper startup suppression
- Vehicle speed v < 3 km/h
- Combination switch (2nd ring) in interval setting or
- reverse gear wiping active

Function sequence for rear window wiper startup suppression
If a door or the liftgate is opened during wiping, the rear SAM control unit interrupts the actuation of the rear window wiper motor. Opening the left front door is recognized by the status of the left front door rotary tumbler switch (A85s1) which is read in by the left front door control unit (N69/1).

Opening the right front door is recognized by the status of the right front door rotary tumbler switch (A85/1s1) which is read in by the right front door control unit (N69/2). Opening the liftgate is recognized by the status of the liftgate rotary tumbler switch (M14/7s1) which is read in by the rear SAM control unit.
The corresponding control unit transmit this information to the front SAM control unit via the interior CAN. The front SAM control unit evaluates it and interrupts the actuation of the rear window wiper motor by sending a corresponding signal over the interior CAN, which is received by the rear SAM control unit.

Re-actuation of the rear window wiper motor takes place once the wiper startup suppression has been activated by one of the following events:
- Vehicle speed v > 3 km/h
- Rear wipe request
- Rear wash request
- Rotary tumbler switch closed and electronic selector lever module control unit (with transmission 722) in position "D" or "R"
- Rotary tumbler switch closed and clutch pedal switch (S40/3) actuated (with transmission 711 and 716)
- Rotary tumbler switch closed and change from circuit 15C to circuit 15R

Function sequence for final wipe
If the rear window wiper is not in the parked position when the wipe function is switched off, a final wipe is made until it moves to the parked position.