In most cars, that small button or set of buttons on the rear-view mirror serves one of a few common functions: it may control auto-dimming glare reduction, operate a built‑in garage-door opener, or connect you to emergency or assistance services. The exact purpose depends on the make, model, and trim of your vehicle.
The precise function isn’t always obvious because manufacturers use different icons and layouts. This article explains the typical options, how to identify which one your car has, and how to use it safely.
Common functions you might find on rear-view mirror buttons
Overview of typical features
Many modern mirrors combine several conveniences into the bottom edge. The list below covers the most common functions you’ll encounter on consumer vehicles today.
- Auto-dimming control: A small switch or pad at the bottom of the mirror can enable or disable the electrochromic glass that automatically darkens in response to bright headlights behind you. In many cars, the dimming happens automatically, but you can override it with this control if needed.
- Garage-door opener (Homelink or similar): Some mirrors include three programmable buttons that can operate compatible garage doors, gates, or lighting systems. You can program them to your remote(s).
- Emergency or safety button: In vehicles with OnStar, SOS, or similar services, a distinct button is provided to request help or connect to a dispatcher in an emergency.
- Display controls (compass/temperature, etc.): In certain trims, a button or control cycles through an on-mirror readout such as a digital compass, temperature, or a brightness setting for the mirror display.
In many vehicles, multiple features share the same physical area of the mirror, with different icons indicating their purpose. If your mirror lacks icons or the ambiguity persists, check the owner's manual or contact the dealer for specifics about your model year and trim.
How to identify what your button does
What to look for on the label or branding
Use these steps to determine the exact function of the button on your mirror, especially if you inherited a used car or are unsure about the model’s features.
- Check for familiar icons or labels on or near the buttons (for example, a house icon for garage opener, a red SOS symbol, or a compass).
- Consult the owner's manual or the manufacturer's website to see which features are tied to your trim and year.
- Inspect the bottom edge of the mirror for branding like Homelink and a set of small buttons—these often indicate a built‑in garage‑door opener.
- Look for a toggle, push switch, or touch pad that matches descriptions for auto-dimming or manual dimming controls.
- If you still aren’t sure, contact the dealership or a trusted mechanic with your car’s VIN or trim level for a precise identification.
Knowing the label and placement helps you use the feature confidently and avoid triggering unintended actions while driving.
How to use these features
Practical usage and safety tips
Once you’ve identified the button’s purpose, follow these general guidelines to use the feature safely and effectively.
- Auto-dimming: The mirror will normally dim automatically at night. If your model has a separate on/off switch, use it to disable or re-enable auto-dimming as needed. This feature is designed to reduce glare from headlights behind you without affecting daytime visibility.
- Garage-door opener: To program and pair with your remote, turn the ignition to on, press and hold the desired button on the mirror while bringing your remote close (about 2–3 inches). Wait for the LED to blink or change pattern. If your garage door uses a rolling code, you may need to press the “learn” or “smart” button on the opener first, then complete the pairing. Test the button to ensure the door opens and closes smoothly.
- Emergency/safety button: Use only in appropriate situations. Pressing or holding the button will connect you to the service provider or emergency system. Follow any prompts from the dispatcher or automated system. Do not misuse in non-emergency situations.
- Display controls (if present): If your mirror can display a compass or temperature readout, use the designated button to cycle through displays or adjust brightness as described in the manual.
Practice using these features in a safe environment to verify operation before relying on them in traffic or at night.
Summary
The button on your rear-view mirror is typically there to simplify safety and convenience: it might dim glare, control a built-in garage door opener, or connect you to emergency services. Each vehicle varies by brand, model, and trim, so a quick manual check or a dealer confirmation is the best way to be sure. With the right knowledge, you can use these features confidently and safely on the road.
What does the flip thing on my rear view mirror do?
Function on the inside rear view mirror. At night when a car behind turns on its high beams the light reflects into your eyes it's distracting. And even dangerous. That's when this feature.
What is the little green light on my rear view mirror?
It's the indicator for the auto-dimming feature on the mirror. You can press that O button on the right to turn it off, but it may just come back on again whenever you start the car. The next question is how to default it to OFF without having to push the O button each time.
What is the little button on my rear view mirror?
But if someone's shining the headlights in your face. You just flick the button towards you and it tilts. It towards the ceiling. So you don't get dazzled and blinded by the the headlights behind you.
Why does my rear view mirror have an auto button?
When this is active, it will automatically adjust your rear-view mirror for you based on headlight glare coming from behind the car. It makes it easier for you to see, and you get to keep your hands on the wheel while driving for safety.