GF82.30-D-2300H Windshield Wiper (WS) System, Function

GF82.30-D-2300H Windshield Wiper (WS) System, Function


The windshield wiper system (WSA) is ready for operation as from "circuit 15R ON".
The windshield WSA is controlled by the SAM control unit (N10). The windshield WSA is activated and deactivated using the wipe switch (S144s4) and the windshield washer system switch (S144s3), which are integrated in the combination switch (S144). The combination switch signals are read in by the MRM control unit (N80) and forwarded over the Controller Area Network bus Class B (interior) (CAN-B) to the SAM control unit.

The SAM control unit reads in the signals of the following components:
- Combination switch over CAN-B from the MRM control unit
- Rain/light sensor (B38/2), with code (JA5) Light/rain sensor, over CAN-B from the DBE control unit (N70)

The SAM control unit actuates the following components:
- Stage 1+2 front windshield wiper relay (K40/9k2)
- Front windshield wiper relay (K40/9k4)
- Windshield wiper motor (M6/1)
- Windshield washer fluid pump (M5/1)

With the windshield WSA system, the following 4 positions can be adjusted using the wipe switch integrated in the combination switch:
- Position "0"
In this position, the windshield WSA system is or can be deactivated. When deactivating, the current wipe cycle is terminated and the front windshield wipers move back to the park position.

- Position "1"
The "windshield intermittent wipe" function is activated in this position. The interval is set to t = 6 s or it is determined by means of the rain/light sensor, with code (JA5) Light/rain sensor.

- Position "2"
The "normal wipe" function is activated in this position.

- Position "3"
The "fast wipe" function is activated in this position.

On vehicles except code (JA5) Light/rain sensor, the interval time is t = 6 s.
If the vehicle speed drops below 5 km/h, the activated windshield WSA system is automatically switched to the next lower position. In position "1", the "windshield intermittent wipe" function, the interval time increases to t = 9 s.
If the vehicle speed increases above 8 km/h, the activated windshield WSA system is switched back to the previous switch position.

On vehicles with code (JA5) Light/rain sensor, the interval time in position "1", "windshield intermittent wipe" function, is continuously determined by the rain/light sensor. If the "windshield intermittent wipe" function is active, then depending upon rain intensity, the system switches to position "2", "normal wipe" function, or position "3", "fast wipe" function.
If the vehicle speed drops below 5 km/h or if the vehicle comes to a standstill, the system switches to the next lower position. In position "2", "normal wipe" function, and position "3", "fast wipe" function, the interval time is always continuously determined by the rain/light sensor.
If the vehicle speed increases again above 8 km/h, the activated windshield WSA system is switched back to the previous switch position.

If the rain/light sensor is defective, the windshield WSA system is actuated as for vehicles except code (JA5) Light/rain sensor.

On vehicles with code (JA5) Light/rain sensor, with "circuit 15R ON", turning the wipe switch to position "1", "windshield intermittent wipe" function, triggers an initialization wipe, i.e. a single wipe cycle is conducted, which frees the rain/light sensor area from raindrops, dirt and salt. The initialization wipe is necessary to ensure correct operation of the rain/light sensor.
If status "circuit 15R ON" is activated and if the wipe switch is in position "1", "windshield intermittent wipe" function, no initialization wipe is performed. The driver must operate the wipe switch again.

In addition, the windshield washer system switch integrated in the combination switch can be used to activate the following functions:
- Pressing up to the actuation point activates a single "touch wiping" function without any window washer fluid.
- Pressing beyond the actuation point for t < 1 s activates the "windshield wash" function with window washer fluid and a single afterwipe.
- Pressing beyond the actuation point for t > 1 s activates the "windshield wash" function with window washer fluid and three afterwipes.

With "circuit 15R OFF", the front wipers remain in their current position. If status "circuit 15R ON" is activated again, the front wipers are moved back to their park positions (completion of wiping).

The "windshield wash" function has priority over the activated "windshield wipe" function, which is set forth following termination of the "windshield wash" function. With the "windshield intermittent wipe" function, the interval window is reset to "0".

On vehicles with code (JA5) Light/rain sensor, any startup of the front wipers is suppressed to preserve the windshield WSA system, when status "circuit 15R ON" is present, v < 3 km/h and the measured outside temperature is < +4 °C.
The startup suppression is deactivated when v > 3 km/h or the combination switch is operated. Deactivation of the startup suppression is active until the next change in status "circuit 15R OFF".

Blockage detection function
The SAM control unit detects that the windshield wiper motor is blocked via circuit 31B.

A blockage of the windshield wiper motor is detected under with following conditions being met:
- Park position not exited after t = 4 s, in position "1", "windshield intermittent wipe" function, and in position "2", "normal wipe" function.
- Park position not reached after t = 12 s, in position "1", "windshield intermittent wipe" function, and in position "2", "normal wipe" function, and in the "touch wiping" function.
- Park position not reached after t = 12 s, in position "3", "fast wipe" function, after 1st request. At the 2nd request, blockage detection is deactivated (emergency operation) within a driving cycle.

Upon recognition of a blockage, the windshield wiper motor is deactivated. If the combination switch is operated again or if the status "circuit 15R ON" is activated with combination switch in position "1", "windshield intermittent wipe" function, position "2", "normal wipe" function, or position "3", "fast wipe" function, then another attempt is made to switch on the windshield wiper motor.