Mirror Magic: How Auto-Dimming Rearview Mirrors Work

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on April 22nd, 2024

Reading Time: 5 minutes
Summary
  • Rearview mirrors refer to adjustable mirrors usually attached to the top of the windshield. The rearview mirror allows the driver to see what’s behind the car. Auto-dimming mirrors offer improved safety and reduced eye strain and driver fatigue by dimming the mirror when needed.
  • An auto-dimming mirror, also known as an electrochromic mirror, dims when needed with the help of an electrochromic gel between two pieces of glass that are coated with electrically-conductive material. A series of sensors trigger the dimming effect depending on the situation.
  • Not all vehicles come with auto-dimming mirrors. They can cost between $100 and $300. You can opt to install anti-glare films as an alternate option.

Vehicle mirrors help keep you safe while on the road. Through the years, manufacturers have introduced many high-tech elements to make mirrors more advanced. In this article, we’ll talk about how auto-dimming rearview mirrors work and the things you should consider when shopping for one.

Rearview Mirrors

Rearview mirrors refer to adjustable mirrors usually attached to the top of the windshield. Its primary purpose is to allow the driver to see what’s behind the car. This mirror will enable you to monitor traffic to prepare for any potential danger while on the road.

How Does an Auto-Dimming Rearview Mirror Work?

Not all vehicles come with auto-dimming mirrors. But many modern vehicles already have them as standard for some trims.

An auto-dimming mirror, also known as an electrochromic rearview mirror, works through the process of electrochromism. This refers to a material’s ability to change color or opacity in the presence of an electric field.

An electrochromic mirror dims when needed with the help of an electrochromic gel between two pieces of glass that are coated with electrically-conductive material.

When you’re out for a ride, an ambient sensor in the mirror monitors how much light there is outside and alerts the mirror control unit. A glare sensor then triggers an electric charge once it senses that the light level is enough to cause glare. The gel changes color because of the current, dimming it enough for you to still see through the mirror. Once the glare is gone, the system switches off, and the mirror returns to normal.

Note that some early interior auto-dimming rearview mirrors simply had a light sensor that automatically tilted the mirror up to the refracted position when a car’s headlights were detected by the mirror’s rear-facing light sensor. You can also tilt the mirror to its refracted position manually on these vehicles.

Note that some early interior auto-dimming rearview mirrors simply had a light sensor that automatically tilted the mirror up to the refracted position when a car’s headlights were detected by the mirror’s rear-facing light sensor.

Richard McCuistian, ASE Certified Master Automobile Technician

Do Vehicles Come Equipped With Auto-Dimming Rearview Mirrors?

Not all vehicles come with auto-dimming mirrors. But many modern vehicles already have them as standard for some trims. For example, the 2023 Honda CRV lists an auto-dimming rearview mirror as one of its interior features. Some variants of the fourteenth generation F-150 like the Lariat and King Ranch, also have these rearview mirrors as standard.

How Much Does An Auto-Dimming Rearview Mirror Cost?

 If your vehicle doesn’t have this type of auto-dimming mirror, you can check out if there are aftermarket options for your ride. The price range can significantly vary depending on your specific vehicle. Most aftermarket electric auto-dimming rearview mirrors are priced anywhere between $100 and $300.

Anti-Glare Films

If you don’t want to replace your existing mirror, there’s another option you can try—anti-glare films. You’ll find basic and professional-grade films on the market. These films are also easy to install, so you won’t have to pay a professional to do it for you.

Installing an Auto-Dimming Rearview Mirror

Rearview mirrors can appear simple to install, but auto-dimming ones can be a bit more complicated and time-consuming. If you don’t want the hassle of connecting wires, we recommend taking your ride to an auto repair shop. You’ll need to shell out money for labor, but it’s better than damaging your vehicle’s windshield or other parts just to install a rearview mirror.

Advantages of Having an Auto-Dimming Rearview Mirror

Any rearview mirror is enough to see what’s behind your vehicle when you drive. So what’s so special about auto-dimming mirrors?

You’ll worry less about glare from behind your vehicle if you have auto-dimming mirrors.

 Here are some of the benefits of having this type of mirror installed:

Improved Safety

Although all states require drivers to dim their high-beam headlights when there is a risk of blinding other drivers, some drivers do not. The glare from high-beam lights coming from other vehicles can disrupt your focus when driving in dark areas. You’ll worry less about glare from behind your vehicle if you have auto-dimming mirrors.

Reduced Eye Strain and Driver Fatigue

Bright lighting can put too much strain on your eyes and impair your vision. Light can scatter inside your eye, causing difficulty focusing on an object. With driving, being able to see things clearly is vital. So if you often do long rides at night, consider installing an auto-dimming rearview mirror. It can help you stay focused, alert, and safe.

Is it Illegal to Drive Without Rearview Mirrors?

It depends on which state you’re currently in. Some states only require two rear-facing mirrors, which could be your side mirrors. Find out which laws apply to your state by checking out this article.

Automotive mirrors aren’t just there for aesthetics. They’re installed to help you maneuver your vehicle and to keep you safe while on the road. For your safety, it’s best to err on the side of caution and repair or replace mirrors as needed to prevent road accidents.

Where to Get a Rear View Mirror for Your Vehicle

If you’re looking for a rear view mirror for your vehicle, look no further than CarParts.com. We have a wide selection of top-notch car mirrors sourced from top brands in the industry.

All you have to do is input your ride’s exact details into our easy-to-use vehicle selector to narrow down your search to the mirrors that can be installed on your vehicle.

Our team of industry experts handpicks all our products to ensure they match industry standards and specifications. They’ve also undergone strict quality checks, so you can be sure you’re choosing among the best possible mirrors for your ride.

Not sure which rear view mirror to choose? We have a 24/7 customer service team ready to answer your questions. Our warehouses are located across the country, so you can be sure your orders will arrive on time.

Check out our selection of rear view mirrors now, and enjoy the best deals!

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician