How Do Rain-Sensing Wipers Work?

Several decades ago, the only settings windshield wipers came with were low, high, and off. Later, an intermittent wiper feature was integrated into many windshield wiper switches, allowing drivers to reduce the frequency of wiper movements based on the intensity of precipitation. The most innovative addition to windshield wiper technology has come in recent years, in the form of rain-sensing wipers.

Rain-sensing wipers turn on when precipitation or another obstruction is on the windshield. The wipers engage on their own and the frequency of windshield wiper swipes is adjusted based on the weather conditions.

So How Do Rain-sensing Wipers Actually Work?

Mounted on the windshield, usually close to or integrated into the rear-view mirror base, is a sensor. Most rain-sensing wiper systems use an infrared light that is projected through the windshield glass at a 45-degree angle. Based on how much light returns back to the sensor, the wipers engage or adjust their speed. If rain or snow, or dirt or another substance is on the windshield, less light returns to the sensor and the wipers turn on independently.

Rain-sensing wipers will turn on faster than you can respond, especially in a surprising situation like your windshield getting splashed by passing traffic. Your vehicle is still equipped with a manual override with at least a low, high, and off switch in the case of rain-sensing wiper malfunction.


The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Make Your Own Windshield Washer Fluid
It's easy to make windshield washer fluid with common ingredients. Homemade washer fluid can be more environmentally friendly than conventional fluid.
How to Replace a Cylinder Head Coolant Temperature Sensor
Signs of coolant temperature sensor failures include sluggish acceleration, hard starting, and a Check Engine or Service Engine Soon Light.
How to Replace a Transmission Position Sensor (Switch)
Transmission position sensors (TPS) switch ensures a car is in Neutral or Park when started and shuts the car down if it's not in the right gear.

Related questions

How do I operate the Speed Dependent wipers?
If your car is equipped with Speed Dependent wipers (these are optional equipment), you have the ability to turn them to intermittent, and then let them be – they’ll automatically speed up with your vehicle, and then slow down when...
Passenger's side windshield wiper not working
The windshield wiper motor linkage may have come off of the wiper transmission. The front cowl would need to be removed for access to check the linkage. I recommend having a mechanic, such as one from YourMechanic, inspect your windshield...
The odometer won't increase or change, it is frozen on 30k miles.
Check the vehicle speed sensor (VSS) on the transmission and see if its unplugged. If the wire is plugged in, then either the VSS is not working or the speedometer gauge is broken. If you need further assistance with your...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com