Wiper and Washer Systems: Description and Operation

STANDARD WIPERS

The two speed, permanent magnet, three brush electric windshield wiper motor has a brush rigging that permits selection of low or high speed. When the control selector is in the low position, current flows through the entire armature winding, causing the motor to run at a slow speed. When the control selector is in the high position, current bypasses a portion of the armature winding, causing the motor to run faster. When the control selector is moved to the park position, the motor will continue at low speed until the park switch outer contacts open, stopping the motor in the park position.

INTERVAL WIPERS

E-100-350
The interval operation of the windshield wiper motor is controlled by a variable resistor in the windshield wiper control switch, which in conjunction with the electronic governor, allows a variable pause between wiping cycles. For normal operation of control switch, slide wiper-washer knob toward right. First position is for interval, second position is for low speed, and third position is for high speed.
When the control knob is placed at the left side of the interval position, the time interval between wiper blade sweeps is at maximum. As control knob is moved toward right, time interval between sweeps is shortened. At first detent position, wiper system will operate at low speed. At second detent position, wiper system will operate at high speed.
The variable resistor in the switch controls the amount of current to the electronic pause control which in turn regulates the operation of the motor for the desired time interval.
Operation of the windshield washers while the switch is in the interval position electrically overrides the governor, causing the wipers to operate at low speed. Normal interval wiper operation resumes when the wash knob is released.