Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. What Does the Switch on the Bottom of the Rearview Mirror Do?

What Does the Switch on the Bottom of the Rearview Mirror Do?

rearview mirror switch

Auto mirrors provide essential visibility to the rear and sides of a vehicle. However, they can also be sources of discomfort – being blinded by the glare of headlights behind you through your rearview mirror is no fun, and reduces your safety on the road. Thankfully, it’s simple to adjust the mirror by using the switch at the bottom of the rearview mirror.

What does the switch do?

If you have a manual rearview mirror, there’s a switch or tab at the bottom. It should move up and down. Changing the switch’s position changes the way the mirror works. Flip it one way and you’re in daytime driving mode, with everything crisp and clear. Flip it the other way, and it changes to nighttime driving mode. The reflection is dimmer (and harder to see when it’s light outside), but it is meant for nighttime driving and dims the glare from headlights behind you.

How the switches work

So, how does the mirror switch actually work? It’s pretty simple, really. Your rear view mirror glass isn’t actually flat – it’s a wedge of glass that’s thicker on one end than the other. When you flip the switch at the bottom of the rearview mirror, the wedge moves. What this does is change the way light passes through it and how it’s reflected back.

In daytime driving mode, the back surface of the mirror is what reflects light and images. When you flip the switch and change the orientation of the mirror glass, the front section is responsible for what you see. Because the light and images must first travel through the back side of the glass before hitting the front and bouncing back to you, the image is dimmer and the glare of headlights behind you is greatly reduced.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

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

More related articles

Symptoms of a Bad or Failing Flexible Clutch Hose
Common signs include difficulty shifting, low clutch fluid, and feeling no resistance at the clutch pedal.
How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...


Related questions

Q: Does a Cracked Mirror Need to Be Completely Replaced?

To determine if a cracked mirror needs to be completely replaced will depend on a few factors. Let's start with the interior mirror, or what is typically called the rear-view mirror. Generally this mirror is only replaceable as an entire...

Q: Brake switch confirmed good, but brake lights not working

The brake lights are turned on and off by the brake light relay in the underhood relay box. This relay is controlled by the body control module and is signaled by the brake switch. Check the relay first to see...

Q: How do I adjust the height of the rear view mirror?

Adjusting the height of the rear view mirror ensures it’s in the correct position to see vehicles behind you. Just move the mirror up or down with your hand to make the adjustments. Make sure you can see behind your...