Wiper Motor: Description and Operation

Operation of The Wiper Motor







The front wiper system is supplied with the necessary voltage from the vehicle electrical system control unit, via a short circuit proof output module and a reverse voltage protection and changeover relay. The wiper/washing functions of the stalk control are read in in the steering column module and converted here into CAN signals which are subsequently evaluated in the vehicle electrical system control unit. Power supply to the wiper motor is interrupted immediately when "ignition off" state applies. When the ignition is switched on again, the wiper is moved into its end position, provided that the wiper functions (intermittent, wiper 1, wiper 2) are off.

The wiper motor is permanently connected to ground and is supplied with positive potential in its respective switching positions. After deactivation of the respective switching positions and in intermittent mode the wiper motor continues to be supplied with positive potential until it reaches its home position. A load switched ground signal is sent to the level 1 terminal immediately after cut-off of the positive potential. The wiper motor thus operates as a generator in short circuit operating mode and is decelerated.

Home position is scanned by a disk cam integrated in the wiper motor. If home position is not detected within the time t(END) as a result of a malfunction, the control system will switch to direct operating mode. Operation of the wiper can then only be continued in positions 1 and 2, whereby the wiper is shut down by way of the wiper switch without returning to its home position.

Technical Data on the Wiper Motor