Your Car’s Rearview Mirror Might Have a Hidden Button You’ve Never Used

You’re probably familiar with the small manual lever on older rearview mirrors that adjusts the angle to reduce glare from headlights behind you. But in many modern vehicles, that simple switch has been replaced—or supplemented—by buttons built directly into the mirror. Depending on the vehicle’s year, brand, and model, those buttons can control several different functions.

One of the most common features is the auto-dimming rearview mirror. Instead of using a manual lever, the mirror has a button that turns the system on or off. Usually, a small indicator light shows when the feature is active. When enabled, the mirror automatically adjusts its brightness when headlights from vehicles behind you create glare. This helps improve visibility at night and allows the driver to keep both hands on the steering wheel.

In some vehicles, the mirror includes several buttons that activate different systems. These features vary widely from model to model and aren’t as universal as the auto-dimming function. They can include controls for home automation systems, emergency assistance services, and other connected technologies.

Rearview Mirror Controls in Some Vehicles

In certain Toyota models, the auto-dimming button and other controls are grouped together on the mirror itself. One of these buttons may operate the HomeLink system, which allows drivers to open or close garage doors directly from the vehicle once the system has been programmed. Some mirrors also include a button that switches between day and night brightness modes to improve rear visibility.

Hyundai is another brand where rearview mirrors often feature multiple buttons for accessing different smart features. Like Toyota, Hyundai vehicles may include HomeLink buttons for controlling garage doors. You might also find a BlueLink button, which connects the vehicle to Hyundai’s digital services. These services can provide emergency assistance and other connected functions. To use BlueLink features, drivers need an active subscription, though many vehicles come with a free trial period when purchased new.

Electric vehicle brand Polestar has taken a slightly different approach. On some Polestar models, a button located at the bottom of the rearview mirror switches the display to a live image from a rear-facing camera. When this mode is active, the camera can automatically adjust its view when the turn signal is activated, helping the driver see the adjacent lane more clearly and potentially avoid collisions.

If your current vehicle doesn’t include these features, it doesn’t necessarily mean you’re out of luck. Replacing the factory rearview mirror is actually one way some drivers turn an older car into a more connected “smart” vehicle. However, installing a replacement mirror yourself carries some risk if it’s done incorrectly. It’s also important to make sure the mirror is compatible with your vehicle in terms of size, mounting system, and viewing angle.

Today’s online marketplaces offer a wide range of aftermarket rearview mirrors. Many include built-in Android systems, GPS navigation, and dash cameras. Some even integrate smart-home functions similar to HomeLink, allowing drivers to control garage doors, gates, and even home lighting directly from the mirror.