Wiper and Washer Systems: Description and Operation

The Permanent Magnet Depressed Park (PMDP) windshield wiper and remote washer pump system consists of a depressed park wiper motor and a washer pump mounted on the washer fluid reservoir.

Based on the type of control switch used and whether an optional electronic printed circuit board is attached in the wiper cover, the system can serve as either a pulse type wiper system or a standard type system. Pulse timing and demand functions are controlled electronically on pulse systems. The pulse system also uses the vehicle speed signal to adjust the wiper delay time. The faster the vehicle is traveling, the shorter delay time between wipe cycles.

Electronic logic circuits on the pulse wiper system's printed circuit board establish all timing and washer commands. If the WASH switch is pressed, a wash is performed for as long as the switch is depressed. The wash action is followed by six seconds of dry wipes before shutoff. With the control switch in the LO or HI speed position, the respective brush circuit is completed to the 12 volt DC source and the wiper motor runs at that particular speed setting.

Moving the switch to the PULSE mode operates the wiper motor intermittently. The intermittent delay can be varied by moving the switch back and forth in the delay mode. An instantaneous wipe can be obtained by moving the switch to the MIST position.