Windshield Wiper Motors & Arms

What is a windshield wiper motor and where is it located?

Your windshield wiper motor is what provides the motion for windshield wipers. Without it, you would have to manually move the wipers back and forth to keep your windshield clear. In fact, prior to wiper motors, drivers did just that, with a lever mounted inside the car. 

Your windshield wiper switch, which is located on the side of the steering column, is what gets the whole process of cleaning your windows going. It is your input to activating and adjusting the movement of the vehicle’s wipers, as well as getting the windshield washer pump to pump washer fluid from the windshield washer reservoir to the washer nozzles, allowing you to clean any debris off your windshield. Many of these are multi-function levers that also include dials and switches to activate other systems, such as the headlights, for example. The lever connects to a switch inside the steering column, which contains the circuitry that sends the driver’s input to the wiper motor and washer pump. Some assemblies combine the lever and switch into one unit. So, when the wiper controls have been engaged to activate your car or truck’s windshield wipers, the windshield wiper motor then uses power from the vehicle’s electrical system to operate a worm gear. The worm gear spins a circular gear. This operates a shaft that moves the windshield wiper linkage back and forth to move the wiper arms which are connected to the linkage, from side to side. The wiper transmission thus allows for the wiper motor and arms to work together without hitting each other. The blades, which are attached to the wiper arms, are then able to clean the windshield as fast - or as slowly – as needed. The wiper motor may not stand out in your mind as one of the most important parts of a vehicle, but in snow or rain, it’s essential to your visibility and therefore your safety. 

The wiper motor is located below the windshield wipers under a cowl that keeps debris out of the heating ventilation and cooling system. Rear window wipers are found on some hatchbacks and vans among other vehicles. These also, of course, have rear wiper motors and arms to power those wipers. The rear wiper motor is usually found inside the door panel for the rear door. 

How do I know if my windshield wiper motor needs to be replaced?

If your windshield wipers won’t budge when you turn them on, move slower than usual, get stuck, or sink below their normal resting level, there may be a problem with your wiper motor. Most of these problems could also be the result of a blown fuse, so check your fuses first before diving into more serious repairs.

Windshield wiper motors are usually grounded through the bolts that connect them to the vehicle’s frame. If these bolts corrode, the motor might not be properly grounded and won’t work. You can check this problem with by giving the motor a gentle whack with a rubber mallet or similar device. If that makes the wipers come to life, it could mean that the grounding was to fault. It could also mean that some connection in the motor was broken and you temporarily whacked it back into place. 

Over time, the electrical connections inside the wiper blade motor may become damaged, or the motor and gears themselves may become worn out. Although it’s certainly possible to open up a wiper motor and repair internal damage, things get pretty complicated in there. Replacement windshield wiper motors are pretty cheap, so you’ll probably find it’s worth the money to save yourself the time and effort. 

Wipers that droop below their normal level when at rest are a special case, although they call for the same solution—namely replacing the wiper motor. The motor contains a mechanism that tells it to stop when the wipers return to the rest position. If this stops working, they’ll droop below that level. 

Can I replace a windshield wiper motor myself?

Replacing the windshield wiper motor should prove relatively easy. Gaining access to the motor may be the most difficult part. You’ll have to remove the cowl—the body panel below the windshield. For safety’s sake, disconnect the negative battery cable before working on the wiper motor. Once you’ve gotten to it, you’ll have to disconnect the old from the wiper linkage, unbolt it, and put in the new one.  The process for replacing a rear wiper motor will be much the same, except you’ll have to open up the rear door panel. 

What are windshield wiper arms and where are they located?

Your windshield wiper arms are the shafts that the wiper blades attach to and are held by. They move back and forth and push the wiper blades across your windshield to keep your windshield clear. They’re pretty simple parts, but they do play an important role. In snow or rain, they are essential to your visibility and therefore your safety. 

The wiper arms attach at one end at the cowl and at the other end to the wiper blades. The windshield wiper transmission, which is made up of multiple linkages, connects the wiper motor to the two wiper arms, transferring the power generated from the rotational movement of the motor when it is activated by the windshield wiper controls into the sweeping back and forth motion of the windshield wiper arms, which the blades are attached to.

How do I know if my windshield wiper arms need to be replaced?

Windshield wiper arms are constantly exposed to the elements, so problems are bound arise over the course of time. If the windshield wipers shake or “chatter” on their way across the glass, or if they’re moving properly but not getting the windshield clean, then there might be a problem with your windshield wiper arms. You should first check that wiper blades are clean and not damaged. Dirty or broken wiper blades will clean your windshield unevenly. If the blades look good, then the wiper arms might not be applying even pressure. This is probably because the arms are bent. Bent wiper arms can be the result of snow or ice, debris, or vandalism at the hands of callow ruffians. While you could try to bend your windshield wiper arms back to a straight position, they’ll never be quite like what they were when they came from the factory, so you’re probably better off getting new replacements. 

Can I replace windshield wiper arms myself?

Replacing your wiper blade arms would be a fairly easy task. Depending on your vehicle, it may help to open the hood, to gain access to your wiper arm connections. If you have a car with windshield washer sprayers on the arms, you’ll want to disconnect those before you begin work. Before beginning work, you should also mark the resting position of the wipers (with something that can be easily cleaned up), so that you put them on in the correct position. Then remove any covering over the base of the wiper arm, remove the nut that attaches it, remove the old wiper arm (this will take a balance of muscle and care to pull it off without scratching the windshield or hitting anything else in the area), and finally install the new arm.