Drivers are baffled by the mystery button on the rear view mirror…so do you know what it’s for?
- People have taken to social media to ask what the little button does
Drivers confused about the function of a “mystery button” on their rear view mirror have found that it dims the rear view mirror to reduce headlight glare.
Some vehicles, but not all, have the button which is very useful for driving in the dark and makes night driving safer.
It looks like a power button and is located, in various models, at the bottom of the rearview mirror.
Motorists have taken to social media to ask what the little button does.
“I’ve had my Jeep for almost four years now and still have no idea what this button does,” one wrote on Reddit.

Not all cars have the button, but it is said to make driving in the dark safer (stock image)
Another asked: “What is this button on my rear view mirror for?”
One commented: “Just a guess – Auto-dimming? When a car’s headlights shine and hit a sensor, they automatically dim your rear view mirror so they don’t blind you?
The SEAT website explained: “The auto-dimming inside rearview mirror provides greater safety when driving at night, as it prevents you from being dazzled by traffic behind you.
“It consists of a mirror element and an electronic system that detects light from the front and rear using photo sensors.
“If the amount of light from behind is more than from the front, the mirror is darkened.”
Some models have two buttons, an “on” switch and an “off” switch.
Mazda says on its website: “When auto-dimming is on, your rearview mirror automatically dims to reduce headlight glare.
“There’s a rear light sensor that can detect when a vehicle behind you shines its headlights at your mirrors.
“Every time the vehicle is started, the auto-dimming function will be activated.”
