Windshield Wiper Motor: Replace or Repair

Most people know it is prudent to look over their windshield wipers and top up washer fluid reservoirs as the monsoon nears. But how many of us spare a thought for the windshield wiper motor? The little motor that operates the wiper arms plays an indispensable role in maintaining clear visibility. Should it fail, the wipers will be inoperative and the car will be unsafe to drive during inclement weather. 

Considering how indispensable a car’s windshield wiper system is to ensuring forward visibility and occupant safety, all components must be in optimal working condition. Here is all you need to know about wiper motors, and what to look out for should one stop working. 

What Is a Windshield Wiper Motor?

Your car’s wiper motor is a simple yet robust DC motor that is powered by the vehicle’s 12-volt electrical system — basically your car’s battery. Its function is to convert electrical energy into mechanical energy, in this case, rotational motion. A simple worm drive gear arrangement reduces the speed of the output shaft while multiplying torque. This output shaft  connects to a linkage system that drives the wiper arms and blades across the windshield in a predetermined path. 

The motor is usually located inside the engine compartment, along the firewall that separates it from the passenger compartment, or shielded under a cover at the base of the windshield. Modern windshield wiper motors usually offer multiple speed settings and a park mechanism that returns the wiper arms to their resting position when turned off.  

Wiper Motor Issues

Windshield wiper motors are extremely durable and designed to last the life of the vehicle. However, just like any other mechanical component with moving parts, they are subject to wear and tear and, can occasionally fail. 

Your windshield wiper system may also stop working due to an issue with a component related to the motor, rather than the motor itself. These may include burnt out fuses, damaged wiring, or the wiper arm linkage. 

Diagnosing the problem correctly will help determine whether or not it is time to replace the wiper motor, and this handy guide will help you do just that. Let’s take a look at some common causes behind an inoperative windshield wiper system. 

Electrical Faults

If the wipers refuse to switch on, or only work intermittently, it may be that current isn’t getting to the motor due to a fault in the electrical system. This could be a blown fuse or relay, a loose connector, or damaged wiring. Such issues are typically minor and easy to rectify, once correctly identified. 

Disconnected or Damaged Linkage

If you can hear the whine of the windshield wiper motor working, but the wiper arms refuse to move or move erratically, your problem is probably located somewhere between the motor and the wiper arms. Take a close look at the linkage that connects the two, and ensure it is intact, properly fastened at both ends and securely mounted. 

If the issue is something simple, like a loose bolt, this can be easily rectified. However, if the linkage itself is broken or faulty, it is time to replace it. 

Damaged or Worn Out Worm Gear 

A damaged worm gear can seem similar to a damaged linkage, as the motor will spin audibly with the wiper arms moving jerkily or intermittently, or not at all. The worm gear is usually housed within the motor assembly and, while it may be possible to repair in some cases, you’re mostly going to have to replace the entire wiper motor.

Noisy or Rough Operation

Rough grinding noises from the wiper motor usually indicate worn out bearings or gears within the motor, and continued usage could lead to complete failure. These small moving parts can be difficult to service or repair, especially in more modern cars. 

Replacement of the entire wiper motor assembly is probably the only option in this case. If you own an older car and parts are not easily available, you may have to trace the offending noise to its source and attempt the repair or replace the affected components. 

Motor Failure or Burnout

While it is extremely rare for modern windshield wiper motors to fail, it can happen. At the heart of the motor is a tightly wound copper winding that generates a magnetic field when electricity is passed through it. It is this magnetic field that causes the motor to rotate. 

The coils of copper wire can sustain damage due to excessive heat within the motor, usually caused by an electrical overload or prolonged operation, leading to motor failure. While a skilled technician may be able to replace and rewind burnt out coils, this can be expensive and time consuming. In such instances, it is usually best to replace the entire motor.  

If buying a second hand car, check the operation of the wipers erratic or jerky movement, strange vibrations or noises, and if the wipers consistently return to the resting position at the base of the windshield.

What To Look Out for When Buying a Pre Owned Car?

When buying a second hand car it is important to ensure that all systems are working properly, and the windshield wipers are no different. The wiper arms should move precisely and firmly, and return smoothly to their resting position when switched off. 

Listen for any unusual knocking or grinding noises from the linkage and the motor itself, which could indicate impending failure. If you notice any irregularities, bring them to the seller’s attention. 

Conclusion

The windshield wiper motor is an oft forgotten component, although it plays a critical role in maintaining visibility and safety in inclement weather. Now that you have a better understanding of its role, location, and operation, you are better equipped to identify early signs of trouble and decide whether repair or replacement is the way to go.