Auto-dimming rear view mirror

Park your Prius at night so you can see lights in the mirror, then turn the mirror on and off. Give it a couple of seconds to respond.

Tom

 

I think it sounds like it is working - your description is similar to my experience. One thing is that it responds to light (i.e., headlights) shining into it, so if there are no cars behind you it won't dim.

It does take some time to go into full dimming mode - I have never felt blinded by lights behind me because it wasn't dimming fast enough, but I have noticed it changing when there are steady lights behind me, such as when I'm driving at night on a highway with lots of cars all around. When it's really in full dimming mode, the headlights seem a bit greenish in the mirror.

I actually think it is superior to regular manually-dimmed mirrors. My eyes are very sensitive to bright lights but I have no problems with reflected headlights and this mirror. I wish the side-view mirrors would dim automatically, too.

 

While driving on a busy multi-lane road after dark, notice how bright the headlights of following cars seem to be in your outside rear view mirrors compared to the auto-dimmed mirror, and then you'll be sure the auto-dimming feature is working.

 

<div class='quotetop'>QUOTE(Doc Willie @ Sep 4 2007, 01:43 PM) [snapback]506829[/snapback]</div>

Yeah, it's working. But if you want it to work even better (dim darker), just put a small piece of black electrical tape over the photo-eye that is on the side facing out the windshield. You'll like the results

 

I think the black tape is a bit of overkill, because it will cause the mirror to dim during the day. I leave my mirror on all the time...why bother turning it off?

Try using a dark transparent film to cover the sensor. This fools the mirror into thinking it's darker outside, but it doesn't think the world is pitch black all the time.

 

I agree with Rick.

At times mine does not seem to be working at all. But it is and sometimes it is slow to change. I always leave it on. Greenish hues have also been observed here.

 

<div class='quotetop'>QUOTE(Rick Auricchio @ Sep 4 2007, 03:14 PM) [snapback]506953[/snapback]</div>

I don't have a problem with it, but I understand the black tape idea works best if it's only about 3/4 covered.

From what I've heard, dark blue is best if you use transparent film.

 

I turned the mirror upside down without putting tape over the front sensor and it seems to be better. Does the front sensor get more "shade" in the upside-down position?

 

<div class='quotetop'>QUOTE(Doc Willie @ Sep 4 2007, 01:43 PM) [snapback]506829[/snapback]</div>

To answer the OP's key question, the easiest way to just test if it is working is to just place your finger over the sensor on the back of the mirror (i.e. facing the windshield). Especially in daylight, it should dim very dark in seconds.

Keep in mind that it uses the windshield-facing sensor to determine the ambient light and the one below the reflective surface to read the headlights behind you. If the ambient light is high, it will not dim no matter how much light is shining on the front (reflective) side of the mirror. In other words, you will not see as much dimming on a street with streetlights as you will when driving an unlit rural country road.

As others have suggested partially or totally covering the sensor on the back of the mirror or flipping it upside down will generally make it dim more.

 

I tried this, and it does make more sense from an optical standpoint (the shape of the upside-down mirror fits better w/ the shape of the rear window), but I found it did the opposite for the dimming.
It seems to dim more when right-side-up.
I can put my hand in front of the mirror when a car's behind me, and the light is more on the bottom than the top of the mirror.