auto dimming rear view mirror

It will provide a light green tint at night when someone is behind you their high beams on. It is variable in it's effect. One way to verify at night while driving is to wait until you see the inside of your car around the windshield light up from the high beams behind you. Then turn off the mirror. The mirror will turn much brighter and whiter over a few seconds. You can then see more details behind you with the headlights clearly brighter. The transition is not instantaneous, it takes 5 or 10 seconds. Sometimes you can see it transition in bright daylight by blocking the front light sensor while it is on. On means the green led is on.

 

Another way is to simply put your thumb over the sensor for 10 or 15 seconds.

I've noticed that when I open the garage door in the morning (garage dark, outside behind the car very light) the mirror will be green-tinted until the forward sensor sees the light and turns the dimming off.