Skip the auto shop - Our mechanics make house calls

Q: How Does the Rearview Mirror Work for Nighttime driving?

asked by on

How does the rearview mirror work for nighttime driving?

A: The answer to that depends on which type of...

The answer to that depends on which type of rearview mirror you have. If you’re thinking of the rearview mirrors we’ve been using for decades, with the little tab on the bottom that flips up or down, let’s talk about them first. Then we’ll cover the newer automatic dimming type.

When we look into a rear view mirror we’re actually looking through a piece of glass that has a mirror mounted at an angle behind it. In the daytime setting, we get full reflection directly toward our eyes. Flipping the tab selects nighttime mode by changing the angle of the mirror. This angle only allows the mirror to reflect a portion of the light coming at us from the glaring headlights behind us. We still see an accurate reflected image, just dimmer one.

  • Tip: The adjusting tab, or lever, is a two-position switch. Move it all the way one way or the other, but not in between.

Automatic dimming rear view mirrors actually darken the tint of the mirror glass in response to the brightness of the headlights shining in from behind. They utilize a technology called electrochromic. This “smart glass” has a thin coating applied and is wired to a controller that sends a low-voltage current to automatically lighten or darken the tint of the glass as required. The mirror may have an on-off switch on the side or bottom to activate this feature. This same technology as being used in “smart windows” of office buildings to lower the heat load from the sun as it moves throughout the day.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Side mirrors will adjust, but not the rear view mirror

Hello! The rearview mirror is not electronically controlled like the side mirrors. To move the rearview mirror you just grab it with your hand and slightly twist it into the position that you wish. My information indicates that there is...

Q: trying to remove the passenger wing mirror cover

The first thing to do is to fold the mirror assembly in toward the car to access the back side. Then use a medium flat tip screw driver and insert it about three inches into the half moon hole near...

Q: Do I Need to Readjust My Car Mirrors Before Driving?

In one word, yes. Anytime that you get into a vehicle, check and adjust your mirrors as needed before you enter any roadway. This ensures that you can see clearly to the rear of your vehicle. We're talking about your...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...