Wiper Motor: Description and Operation

Pulse Wiper Motor:

MOTOR DESCRIPTION
The pulse windshield wiper is a permanent magnet positive park pulse wiper.
The pulse and demand wash functions are controlled by a plug-in printed circuit board enclosed in the wiper's die-cast aluminum housing cover.
Internal parts of the wiper motor assembly, field magnet, armature, drive gear, park switch actuator and brush holder assembly are enclosed in an aluminum die-cast housing with a plastic cover. The housing and cover are attached to each other by seven rivets. A radio frequency interference suppressor is located in the terminal connector on the wiper motor. A strap attached to one of the motor bolt hole grommets provides a ground for the suppressor. An automatic reset type circuit breaker located on the motor brush holder assembly protects the motor. A fuse in the fuse block protects the vehicle wiring.
There are four terminals which are lettered for illustrative purposes. The function of each terminal is covered in the explanation that follows.
Use care when disconnecting the lock-type connectors that attach vehicle wiring to the wiper.
The wiper motor has three brushes: common, low speed and high speed. When the ignition switch is ON, a (+) 12V circuit is applied to both the low and high speed fixed contacts in the multi-function lever. The low and high speed brushes are connected to the multi-function lever through terminals C and D. The armature is grounded through the common brush via the ground strap.