how does it work? what tragger it? sometime it doesn't turn on even at night and sometime it turn on even on day time, what gives?

 

The sensor to dim the mirrors (all of them) is located on the backside of the rearview mirror.
You will see a little hole there. It recognizes when light is behind you (ie. another car), and so dims the mirror.
However this only happens when a sensor on the front of the mirror also recognizes that it is nighttime
(or not enough light in your parking garage, etc).

Oh - the dimming function is also disabled when you are in reverse - for obvious reasons.

 

My auto dimming mirros sometimes works sometimes doesn't work, Any sugestions?

 

haha it's really weird.. my rearview.. uhh well it's kind of retarded. it got stuck a while ago, so like 3/4 of it is dimmed, and the top like 3/4 of an inch is undimmed.. kind of like a squiggly line across horizontally.. it happened randomly i got into my car and looked up and it was like that. sometimes the line shifts slightly and i can see that it has a different squiggle pattern. is there any way to like reset it?

 

Good to know.. I never noticed though. If only Audi put that much thought into the design of some other parts[&:]

 

no its shot... my ex's acura did same thing. get a used one from someone whos parting out. or try to deal with it. that type of thing would get to me though.

 

It's stupid to drive night time w/out dimming mirros, it's driving me CRAZY !@#$%

 

If the lights from the car behind you aren't hitting the sensor in the review mirror then your mirrors won't dim. The all dim at the same time based on this. Annoying when the light is bright in your side mirror but not in the rearview.

 

correct

 

How $$$$$ for a new inside rearview mirror?