Wiper Motor: Description and Operation

A permanent magnet type wiper is used on CK and G Series. The motor parts-field magnets, armature, drive gear etc. are enclosed in a two piece sheet metal housing. For purposes of explanation the housing halves are referred to as upper and lower housing. The two housings are attached to each other by ten extrusions which are staked over.

The wiper 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.

The wiper motor can be operated only when the ignition switch is in the "run" or "accessory" position.

The wiper motor has three brushes; the "common" the low speed, and the high speed. When the ignition switch is "ON," power is applied to the common brush. The low speed and high speed brushes are connected to their respective ground via the control switch. When the control switch is positioned at "HI" or "LO" speed, a ground path is connected to the high or low speed brush in the motor. The motor runs at the switch selected speed.

In order to have the wiper blades stop in their normal park position and the wiper motor shut off properly, the motor must run in LO speed. When the control switch is moved to the OFF position, the low speed brush circuit goes through a park switch located in the gear housing and then to ground at the control switch. The park switch is normally closed and this allows the wiper to keep running. When the wiper blades reach their park position, the cam on the gear opens the normally closed park switch, which turns off the wiper.