Facelift Autodim Rear View Mirror (MY17 On/off Button)


Registered User
Apologies if this is a duplicated post but I searched Auto dim mirror and could only see retrofit threads.

I also remember reading somewhere on here someone posted a question re the mirror in the MY17 cars but I can't find that either and think it was embedded in to another thread?

Trying to figure out if the mirror on sisters car is auto dim. I'm used to the mirror having a button on it which you can switch on / off but the one on the A3 doesn't have this?

Is this right now - new technology etc

Thanks in advance


Registered User
I have the Auto dimming rear view mirror on a facelift S3, no button just a sensor on the back left side.


Registered User
The rimless mirror in ours doesn't have a switch/button. If it's a non automatic mirror it will certainly have a leaver to manually dip it.


Registered User
Brill thanks...out of interest how does a sensor at the back of the mirror work?

Pretty sure the sensor on the front of the mirror isn't for the auto dimming rear view mirror. What use would a sensor on the front of the mirror be when the light is coming from the back? haha. I believe there is a sensor behind the mirror glass, but facing toward the back of the car, this then reacts with light and automatically dims.

I'd imagine the sensor on the front of the mirror for auto wipers? To sense how much rain is on the windscreen


Well-Known Member
VCDS Map User
There's a sensor front and back of the mirror housing - if the one at the back detects more light than the one at the front then that means a bright light source is behind ie, dazzling headlights, and so the mirror dips. Sounds like on the F/L the rear facing sensor could well be hidden behind the glass - that's neat !!

Auto lights and wipers sensor is stuck to the windshield.


Registered User
Took a real poor picture but there's a sensor at the top

Obviously hadn't seen this until it came out in the picture


Well-Known Member
Gold Supporter
The sensor on the rear of the mirror (facing the windscreen) just detects whether it's daytime or nightime, since auto dipping mirrors don't dip in daylight.

There is a sensor of the front of the mirror that detects headlights approaching from behind you, which dims the mirror electronically by switching on an darker LCD mask.