# Hidden sensor in rear view mirror?



## PaulK (Oct 2, 2017)

There appears to be some sort of sensor (or additional cabin facing camera) inside the rear view mirror. It is very hard to see, it's like a 2-way mirror. You can see it if you shine a very bright light into the mirror at an angle.

I was able to capture a faint image of it, see the attachment.

I put this in "Tech Talk" in the hopes someone might open up their mirror to se what this sensor is. My hope is that it will enable the dimming mirrors to auto-dim when headlights shine in from behind. The consensus is that presently the mirrors just dim based on time of day when in Drive.


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## SoFlaModel3 (Apr 15, 2017)

PaulK said:


> There appears to be some sort of sensor (or additional cabin facing camera) inside the rear view mirror. It is very hard to see, it's like a 2-way mirror. You can see it if you shine a very bright light into the mirror at an angle.
> 
> I was able to capture a faint image of it, see the attachment.
> 
> ...


Try shining a flash light on that spot and see what happens. Side note it looks odd and off centered...?


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## garsh (Apr 4, 2016)

PaulK said:


> There appears to be some sort of sensor (or additional cabin facing camera) inside the rear view mirror.


For most cars, that's the sensor used to determine when the mirror should be dimmed. When it senses light (from a car's headlights), it dims the mirror.

I don't know if Tesla makes use of this sensor though.


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## PaulK (Oct 2, 2017)

Yes, the little port is not centered.

I’ve shined a light into it at night and can’t see anything change. Mirror dimming, High beam behavior and screen brightness are not affected by bright light being shined into this port. 

I read a post on TMC that says the port for the light sensor for the Model X is inside the mirror - so I imagine that’s what this is for, it’s just not active yet for some reason. 

Related subject, where is the sensor that determines the screen brightness?


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## GDN (Oct 30, 2017)

Agree, that would likely be the dimming sensor for if a car is behind you. There is another recent thread all about the dimming mirrors having very odd or non-standard behaviors. Staying dimmed at all times. or not dimming when they should. Could be a difference in the already darkened back glass, plus many of us have tinted it as well. I'm guessing this one sensor controls all of the mirrors as well.


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## PaulK (Oct 2, 2017)

GDN said:


> Agree, that would likely be the dimming sensor for if a car is behind you. There is another recent thread all about the dimming mirrors having very odd or non-standard behaviors. Staying dimmed at all times. or not dimming when they should. Could be a difference in the already darkened back glass, plus many of us have tinted it as well. I'm guessing this one sensor controls all of the mirrors as well.


If it is a sensor it's not functioning at all right now. At night, my mirrors are darkened. If I cover this part of the mirror, or shine a bright light into it, there is no difference. I'm rather certain it's just based on time of day, presently.


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## GDN (Oct 30, 2017)

Got to test and experiment a bit today. Left the house at 6:30 AM still dark. All mirrors darkened with the lights on and remained darkened. On the way home before dark, I turned the lights on manually and the mirrors did not darken. After dark on the way home, pulled in to 7-11, got in to leave. The lights came on automatically and the mirrors darkened, put it in reverse and they stayed dark. Nothing would make them lighten back up, which I would really want especially when backing up. Definitely doesn't seem to be using any light sensor as of now, which every other vehicle that I've owned has done - only darken when bright lights were behind me, but always in reverse they would lighten back up.


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