Wiper system (WSA), function - GF82.30-P-0003RC

MODEL 171.4 as of model year 09/YoM 08 model refinement package 

General function requirements  C. 15R On

Wiper system (WSA) in general  The wiper system actuates the windshield wipe and wash function.

The wiper system comprises the following subfunctions:  Function sequence for braking wiper motor (M6/1); Function sequence for wiper motor antilock device; Function sequence for final wipe.

Further partial functions are described in separate documents:  Function sequence for wiping windshield, function; Function sequence for wiper start suppression function; Automatic speed reduction of wiper system, function (without code (494) USA version); Windshield washer, function; Headlamp cleaning system, function (with code (600) Headlamp cleaning system); Washer nozzle/washer nozzle hose heater function (with code (875) Heated windshield washer system).

Function sequence for braking wiper motor  The wiper motor is braked if the wipers are to be stopped in the park position from active operation. To brake the wiper motor, the motor winding is short-circuited via a field-effect transistor by the driver-side SAM control unit with fuse and relay module (N10/1).

The wiper motor has a cam switch for recording the park position. When the motor runs through the park position, the cam switch is actuated. The signal of the cam switch is read in by the driver SAM control unit.

Function sequence for wiper motor antilock device  A lockup of the wiper motor is detected by the driver SAM control unit by the absence of cam switch signals in the wiper motor during an active wiper actuation. If the cam switch signal is missing for longer than 4 seconds in wiper stage 2, the driver SAM control unit switches the wiper motor back to level 1. If the signal is still missing for another t = 8 s, the driver SAM control unit switches off the wiper motor. If during this t = 8 s a signal is received from the cam switch, the wiper motor is switched on again to stage 2.

The driver SAM control unit switches off the wiper motor when wiping in stage 1, if the cam switch signals are missing for more than t = 12 s.

If the corresponding function is requested again by pressing the combination switch (S4) or if circuit 15R is switched on again, the antilock device is canceled in all instances.

Function sequence for final wipe  If the combination switch is reset to the 0 position and if the wiper arm is not in the park position, then it is moved to the park position by the wiper motor.

If the engine hood is opened on vehicles with code (551) Anti- theft alarm system (ATA [EDW]), the wiper motor will come to rest at the position it is in at that time.