Windshield Wiping/Washing

Windshield Wiping/Washing

Purpose of the System
The windshield wiping/washing functions are controlled by a separate wiper module (WWM). The system has never been directly controlled by the ZKE, even though it is a body electrical system.




The system has four wiping stages including one interval wiping speed when the ignition is in position KL R or KL15. The wiper motor output control is by the WWM located behind the glovebox.

System Components - with Principle of Operation

Wiper Stalk Switch Input
The wiping stage inputs are through a coded combination switch that supplies a ground signal to the WWM. The wiping stages include:

Single (S): Momentarily holding the wiper switch down in the single position provides a momentary ground signal to activate a single sweep in slow speed.

Slow (I) and Fast (II): The stage I and stage II wiping speeds are road speed dependent. Stage I switches to intermittent when the vehicle is stopped and stage II switches to stage I when stopped.

Windshield Washing: The wash request provides a switched ground it input to the WWM by pulling the stalk rearward. The WWM activates the windshield washer pump directly. When the washing function is activated, the pump runs as long as the switch is held. The wipers switch on and will continue to for 3 wiping cycles after the switch is released.


Intermittent: The interval time of the wipers is vehicle speed dependent. As the vehicle speed increases, wiping interval times decrease. This timed interval is set in the control module and is not programmable. The programmed intermittent cycles are as follows:

Blocking Protection
The wiper module receives a feedback signal from the wiper motor when the wipers are switched on. If this feedback signal is missing for several seconds after the wipers are switched on, the module will switch the motor off.

The wiper switch must be moved to the off position before another attempt can be made to turn the wipers on. If this blocking protection has activated several times, the ignition must be cycled before the wipers can be switched on again.

The wiper module is not connected to the diagnostic link for troubleshooting purposes. Standard troubleshooting procedures using Electrical Diagrams and DISplus multimeter must be employed to diagnose the wiper/washer.


System Components: Inputs - Processing - Outputs