How Does a Car Windshield Wiper Work?

Windshield wipers make it possible to drive in the rain and snow, and also clean the windshield when it is dirty, so that the driver can drive safely. The windshield wiper system is comprised of the wiper switch, the wiper motor, the washer switch, the washer motor, the delay box and wiring from the ignition and the fuse panel.

Power runs from the fuse panel, when the wiper switch or the washer switch is activated. The wiper switch is fused by the ignition. When it is activated, the power goes from the wiper switch to the wiper motor or the delay box. If the user chooses a delay, the power will run through the delay box (fast or slow), then to the wiper motor. If the wipers are turned full on, the power goes from the switch to the wiper motor. Most wiper motors have two speeds---low and high. When the wipers are turned off, the wiper motor closes a switch (inside the motor) setting itself to "park." The park function causes the wipers to stop at a preprogrammed place---the bottom of the windshield.

If the user wants to use the washer, power runs from the wiper switch on the steering column to the washer switch in the wiring, then to the washer motor to pump fluid from the windshield washer tank, up through small, rubber hoses and onto the windshield. When the washer is activated, the wipers will automatically come on for a few seconds, then will park themselves.

The wipers themselves are metal or plastic arms, which carry rubber blades. The wiper arms are connected to the wiper motor via a series of arms and bushings. When the windshield wiper motor turns, it moves the arms that are hooked to the motor and the windshield wiper arms, therefore moving the arms holding the blades back and forth across the windshield. The rubber on the windshield wiper arms works like a squeegee, wiping water, ice and snow from the windshield.

Because the wiper blades are in direct sunlight much of the time, they tend to dry out and crack or get hard. When the rubber gets hard, it will not clear the windshield, and the blades will need to be replaced. The actual blade can be changed out with a refill, or the user can purchase the whole blade and arm. New arm blades snap into the visible arms on the windshield.