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When it comes to safe and efficient windshield wiper operation, everything begins with the windshield wiper motor, as all the other components are purely mechanical.



What Is a Wiper Motor?

The wiper motor incorporates a simple brush driven engine that is linked to a worm gear to help convert the energy produced into usable power. The primary job of the motor is to produce reliable output, and a typical motor also contains a mechanism that allows its output to be varied and switched off strategically.

How Does the Wiper Motor Work?

When the motor is activated, power is generated and sent through the worm gear mechanism to increase the amount of torque and reduce the speed of motion. If it weren’t for this gear, the mechanism would not have enough strength to activate the wiper from a stop, while the speed of rotation would be too fast. When the speed is varied, different terminals reconnect within the motor so that current flows through high or low speed brushes internally. When everything is switched off, power is diverted to a special “parking switch” until the gear rotates to a point where it operates a parking switch plunger, killing the power when the blades have rotated back towards the bottom of the windshield.

How Are Wiper Motors Made?

Wiper motors incorporate a motor based on a permanent magnet, which is wound with traditional copper wire. Several switches are found next to the motor, which activate the various speeds, or divert power to the parking switch. Motors can contain various electronic circuits, especially in the more complicated motors fitted to luxury cars.

Why Do Wiper Motors Fail?

  • The wiper module that sends a signal to the motor may fail.
  • The associated fuse may blow.
  • Switches may fail to operate.
  • Internal parts may become clogged with debris.

What Are the Symptoms of Failure?

  • Blades may only operate at one speed.
  • Blades may not be able to operate at high speed.
  • Blades may not return to their correct “parking” position.
  • Blades may refuse to move altogether.

What Are the Consequences of Failure?

  • The driver will not be able to see clearly for safe vehicle operation.

Windshield wiper motor repair is not feasible in most cases, and the unit will need to be replaced in its entirety.

If you have questions or concerns about wiper motors or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.