Wiper Motor: Description and Operation
Base Wiper:
Internal parts of the wiper motor assembly, field magnet, armature, drive gear, park switch actuator and brush holding 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. The wiper is equipped with a radio frequency interference suppressor which is located in the terminal connector on the wiper motor. A strap is attached to one of the motor bolt hole
grommets to provide a ground for the suppressor. The motor is protected by an automatic reset type circuit breaker located on the motor brush holder assembly. A fuse located in the fuse block protects the vehicle wiring.
As shown, the base wiper motor has three brushes which are referred to as common, low speed and high speed. When the ignition switch is on, 12V plus circuit is completed to both the low and high speed fixed contacts in the column switch. The low and high speed brushes are connected to the column switch through terminals 2 and 1. The armature is grounded through the common brush via the ground strap.