Function of Auto-dimming Mirrors and How to Confirm if Your Car Has One.

Function of Auto-Dimming Rearview Mirror

Glare Reduction:

1. Uses light sensors (front-facing for ambient light, rear-facing for headlights) to detect bright lights from trailing vehicles.
2. Darkens electronically (via electrochromic gel) within seconds, reducing glare without blinding the driver.

Safety & Convenience:

1. Eliminates the need to manually flip the mirror's "night mode" lever
2. Prevents temporary vision loss and eye strain, improving nighttime driving safety
3. Often works with auto-dimming side mirrors on higher-trim vehicles.

How to Check If Your Car Has One

Step 1: Visual Inspection

Look for sensors:

Front (driver-facing): Small circle/rectangle (ambient light sensor).

Back (rear window-facing): Similar sensor for headlight detection.

Check for a button:

An "On/Off" switch (often labeled ⚡/AUTO) on the mirror’s underside.

No manual lever:

If there’s no flip-tab for night mode, it’s likely auto-dimming.

Labels:

Words like "Auto-Dim," "Electrochromic," or a brand logo (e.g., Gentex).

Step 2: Simple Test (Flashlight Method)

• Park safely (engine on/accessory mode).
• Cover the front sensor (facing you) with tape or your finger.
• Shine a bright flashlight at the rear sensor (back of mirror).
• Watch for dimming:
• The mirror should darken within 5–10 seconds and clear once light is removed.

Step 3: Check Owner’s Manual or VIN Decoder:

•  Check your car's owner's manual for information about the features included in your specific model and trim level. Search "mirror," "auto-dimming," or "electrochromic" in the index.
•  Some online tools allow you to enter your vehicle's VIN (Vehicle Identification Number) to see a detailed list of features and options. 

Step 4: Indirect Clues

•  Side mirrors: If they also dim at night, your rearview is likely auto-dimming.
•  A connector plug behind the rearview mirror strongly suggests it has a powered feature—most commonly auto-dimming.

Key Signs You Have It

✅ Yes	❌ No
Sensors on front & back of mirror	Manual flip-tab lever present
On/Off button	No sensors/buttons
Darkens during flashlight test	No dimming in test
Listed in manual/window sticker	Basic mirror design

Connecting FitDVR Dash Cam power adapter directly to your auto-dimming rearview mirror's connector plug is a popular and clean installation method, most Make and models have this function and its a top choice for many drivers. To confirm your vehicle’s compatibility, please contact our support and we will help you to find the correct product for your car.