Wiper Motor: Description and Operation

Fig. 1 Permanent magnet type windshield wiper motor:

Wiper motor internal components, including permanent magnet fields, armature, brush holder, gear train and park switch, are enclosed in a two-piece housing which is held together by ten staked extrusions. The brush holder and motor
run terminals are at one end of the motor, and the gearbox and park switch at the other end, Fig. 1. Motor operation is controlled by three brushes, common, low and high speed.
When ignition switch is in On position, battery voltage is supplied to the common brush through a fuse in the fuse block. Motor speeds are determined by completing the low or high speed brush circuit to ground at the wiper switch. Pulse wiper operation, if equipped, is controlled by a variable resistor in the wiper switch and by a pulse module connected between the wiper motor and switch.