Windshield Wipers Turn On by Themselves – Causes and Fixes

When windshield wipers turn on by themselves, especially when it’s raining or snowing, it is a sign that they are faulty. Fortunately, we know some common reasons windscreen wipers will start working when not instructed.

This article will discuss these causes and proffer practical solutions to them. We’ll also answer pertinent questions concerning the topic and mention some ways to prevent this occurrence.

Why Do Windscreen Wipers Turn On by Themselves?

Windscreen wipers turn on by themselves when there’s a broken motor or a faulty wiper switch. This is why the car won’t start windshield wipers turn on by themselves without anyone’s intervention. Electrical issues in your car can also trigger wipers.

However, when the wipers begin working during rain or snow, they are likely turned on by a rain sensor. Other reasons include moisture in the relay compartment, a broken stalk, dry dielectric grease, a bad body control module and a wrongly-positioned rubber gasket.

Fortunately, you can solve some of these issues if you know your way around electrical components. Nevertheless, you can count on auto electricians to help you replace the entire wiper system.

• A Broken Windshield Wiper Motor

The wiper motor is a small electric gadget that controls the movement of the wiper across the windscreen. It is usually found on the firewall or under the base of the windshield. Vehicles with rear windscreen wipers have a separate motor that operates them.

The motor can get weak and malfunction due to extensive usage or intrusion of foreign objects. When this happens, you’ll observe that it operates at the same speed or the arms stop in the middle of the windscreen, even when you turn it off.

The wiper motor is malfunctioning when the wipers turn on when starting car. This phenomenon happens intermittently and can be distracting when driving. The wiper blades get stuck to the surface of the windscreen, and forcing the motor to move them can cause its fuse to blow. A blown fuse can impede the full functions of the motor and cause the wipers to turn on and off automatically.

• A Faulty Electrical Windshield Wiper Switch

The switch controls the entire system, allowing it to activate or deactivate depending on the driver’s inputs. The switch is connected to a knob near the steering wheel or a button on the dashboard.

A malfunctioning switch will fail to properly respond to the driver’s input, activating the wipers when they shouldn’t. That is why you’ll see the wipers turn on by themselves.

• Car Electrical Problems

Sometimes, car electrical issues can cause the windscreen wipers to turn on automatically. The wipers run on electrical power supplied by the car battery. If the battery is faulty, it could affect them, making them work when not instructed. A blown fuse or clogged electrical motor might also be the root cause.

A faulty wiring system caused by improper electrical installation can trigger the wipers. This problem usually occurs after a less-skilled auto-electrician works on your car’s steering column. For example, their faulty wiring could allow some voltage to escape the motor to the wipers causing them to turn on. That’s why we encourage drivers to allow professional, skilled auto-electricians to handle their car’s electrical problems.

• Moisture in the Relay Compartment

When moisture seeps into the relay compartment, it can trigger the windscreen wipers. This problem is common during the rainy season for obvious reasons. Moisture causes short circuits in the relay compartment, which turns the wipers on. Fortunately, solving this problem is easy, which we’ll come to later.

Also, cars with rain sensors will activate the windscreen wipers when they sense enough moisture on the windscreen. The sensors are usually located around the interior driving mirror and can adjust the speed of the wipers depending on the density of the moisture on the windscreen. Obviously, this doesn’t need any repairs, as it is a normal vehicle function.

• A Faulty Park Switch Allowing Unrestricted Voltage Flow

A park switch is a component that regulates electricity flow from the battery to the wipers. If it is broken, it will either allow a continuous flow of electricity to the wipers or stop it. In the case of the former, the continuous flow of electricity will cause the wipers to turn on. This scenario can occur even when the car is switched off because the wipers draw unrestricted electrical current from the battery.

Thus, the battery runs down quicker than expected due to the constant pressure from the park switch. The location of the broken park switch in the steering column complicates fixing it. Thus, we recommend you ask a professional to help you out.

• Dried Dielectric Grease Conducting Electricity

The grease is smeared on the relays, and it works to prevent electrical arcing. Electrical arcing is when electricity travels across a gap in a current, which can cause serious injuries. This grease can dry up due to overheating, and when it does, it can allow voltage to pass through it to turn on the wipers.

• A Broken Relay

A relay is a small box in the windshield system that instructs the wipers based on the driver’s inputs. It tells the wipers to come on or off. Thus, if the wipers were on when the relay became faulty, they might stay on even if the driver switches them off. The relay may be the reason the windshield wipers work sometimes.

How To Fix Windscreen Wipers That Turn On by Themselves

To fix windscreen wipers that turn on by themselves, start by repairing or replacing faulty components. You’ll have to perform certain steps to know if the component is faulty and whether it needs repairs or replacement. Then you can then fix the issue to ensure your wipers work again.

The tool needed to test the windscreen wipers is a multimeter, and then someone to help you. First, take preventive measures by disconnecting the negative terminal of the battery. Next is to test the wiper’s motor continuity to ensure it is working properly. If it isn’t working well, then you need to replace it.

• Replacing the Wipers’ Motor

You’ll need screwdrivers and drive sockets to replace the motor. First, consult your car manual to know the location of your motor and remove any screw used to hold it in place. Now, disconnect the electrical connector from the motor with a flathead screwdriver. Remove the bolts connected to the motor with a socket wrench and pull out the old motor.

Next, install the new motor, reconnect the electrical connector, and then screw the new motor with a screwdriver. Also, replace the bolts to ensure the motor is firmly in place. Reconnect the battery’s negative terminal and check whether the wipers are working. If they are, your job is done.

• Replacing the Windshield Wiper’s Switch

You need to find the switch, usually located on the steering column near the bottom. Then remove the screws connected to the switch and remove the electrical connector at the back of the switch. Next, remove the switch from its housing and replace it with a new one.

Now, return the electrical connector and the screws to the proper positions. Test the switch by turning on the wipers to ensure it works properly. Finally, reassemble all the other parts you took out to get to the wipers’ switch.

• Replacing a Blown Windshield Wiper Fuse

Replacing a blown wiper fuse is easy as pie. Just locate the fuse, which can be found in different positions based on your vehicle type. Thus, contact your car’s manuals for assistance locating your vehicle’s wiper fuse. When you find it, simply pull it out and replace it with the new one and test if it works.

The same applies to a faulty windshield wiper park switch. Ensure you locate the switch attached to the steering column. Remove the switch, replace it with a new one, and then test to check if the wipers work. Allow a mechanic to help you replace your blow fuse or park switch if you find it difficult to do it yourself.

Frequently Asked Questions

– What Is the Best Way to Stop Rain-Sensing Wipers?

The best way to stop rain-sensing wipers is by turning their level of sensitivity to low and moving the wiper lever down. This stops the lights and wipers come on by themselves when the sensors detect a small amount of rain. The sensors will activate if they detect heavy rain.

– What Are Signs of a Bad Windshield Wiper?

The signs of a bad windshield wiper are when the windshield wiper works sometimes and other times they don’t. Also, when the windshield wipers won’t turn off even when the driver switches them off. Finally, when the wipers turn on by themselves, then there’s a problem.

 

Conclusion

So far, we’ve looked at several reasons why windscreen wipers turn on by themselves even when the car is off and given some practical solutions.

Here’s a recap of all that we’ve discussed:

• The reasons a wiper will turn on automatically include a blown wiper fuse, faulty wiring, a broken wiper motor and a damaged park switch.
• Other reasons are electrical problems in the vehicle, dried dielectric grease, broken relay or moisture in the relay compartment.
• The only way to repair most of these causes is to replace their faulty components with new ones and test them to ensure they work well.
• Replacing components of the wiper system like the fuse, relay, park switch and motor is straightforward, but the wires and electrical problems require a specialist to fix.
• Signs of a bad windshield wiper include working intermittently, turning on automatically, or not responding appropriately to the driver’s inputs.

In some cases, wipers turn on when starting a car, and this is normal if only the driver refused to turn them off by switching off the car. However, if the driver switched off the wipers before turning off the car, then you’ll need to run some tests to determine the cause of the problem.