Self-darkening rear view mirror

If you look closely, you can see it has a photocell facing forward, and a photocell facing rearward. It compares the brightness forward (so it doesn't dim as much when it's light out) to the brightness from the rear (so it dims more when stronger light falls on that cell). If you put some partially light-absorbing film over the front sensor, it will tend to dim more, or you could put the same stuff over the rear sensor, and it would tend to dim less.

The Prius presents an interesting design issue because of the split rear window. Depending on the height of the car that's following me (or height of their headlights, anyway) and their following distance, and also my height and the aim of my mirror, sometimes their headlights shine all over inside my car, including right in my mirror and full-on in my eyes, but the shadow cast by the spoiler just happens to fall right at the bottom edge of the mirror where the sensor is, so it doesn't sense the light, and it doesn't dim.

And somehow, people following me seem to have an instinctive sense for the exact right following distance to make that happen, and maintain it for 20 miles.

There was a post here some years back where somebody just rotated the mirror so it's upside-down with the buttons and sensor at the top edge, and it solved the problem for them.

 

i think it senses headlights. i don't like them, prefer the cheapo flip mirror, but i'm sensitive to glare.

 

I agree on the cheapo flip mirror. My 2015 being salvage, the windshield was replaced and they stuck on a plain old flip mirror, which I have missed terribly for years now. Everybody has lasers nowadays for headlights...especially the high trucks which from behind is like having a WWII search light in your rear window.

 

a lot of todays headlights are illegal, or should be

 

Yes everyone hates the new headlights except the people who have them.

I get people flashing their headlights at me all the time and they are on low beam.

 

My 2005 had the automatic mirror. I hated that thing!!!

 

…same here, and I prefer to dip my own headlights, floss my own teeth, and wipe my own bum (so many things are getting automated these days, "…Arms that can only lift a spoon
You see everyone's gone, everybody's gone
Everyone's gone to the moon
Everyone's gone to the moon" (Kenneth King)

 

I thought I was the only one who never liked those auto darkening mirrors.

 

Ah, there are but few of us still remaining! I love driving, and that includes having total control of everything in my car (all the controls, that is!) and that includes gears, engine, clutch, brakes, lights, ventilation, heater, air-conditioning, music, wipers, seat-belts etc. etc. It saddens me when I see just how society is being dumbed-down!

 

I’m still trying to figure out how to set default mirror to off when engine on ready. Haven’t had the long chance to jump on. Techstream for capability.

 

Ahh, the essence of projection lights. For me, the reason for people wanting brighter lights is because the person coming towards them has bright lights and once you pass the cars, your eyes take longer to adjust back to a level you can see. So, people buy the brighter lights, thinking that the issue has been solve. Well it has, but the main problem hasn't been bulb brightness, it's our eyes trying to adjust back after being hit with bright lights, thus the contiuning cycle of brighter and brighter lights being sought.

 

True...I hear people say "they're safer because now I can see so much better at night!". Problem is, everyone else is blinded so they only feel safe, not understanding the other drivers can't see anything at all. I've had cases where I had to just hope nothing rand out in front of me or hope that I don't run off the road until those atomic headlights pass by me.....totally blinded sometimes for up to 4-5 seconds.

 

I am glad when the days get longer and I am usually home before dark when I can be. I don't like blinding people but what to do about it and I don't see it getting any better as brighter and brighter headlights come out. It doesn't help getting older and your night vision deteriorates either.

 

Yeah, my rear view mirror usually does not dim. It does occasionally so it is not broken, but most of the times it does not dim even though there are very bright lights in the mirror and I want it to dim.
I've also assumed this is connected to the spoiler and I've tried turning the mirror 180 degrees to see if the sensor would pick the lights up better, but that made no difference. Now I'm just thinking if I could mod the mirror to have the button not cancel the auto dimming, but force the mirror to dim.

It is incredible that this flaw was not spotted by the Toyota testers.

 

If I can pull far enough ahead or drop far enough back toward the following car so the light from their headlights actually lands on the sensor then my mirror will dim.

The trouble is just that the following driver usually really likes the exact following distance where that doesn't happen.

 

I'll preface this with the admission that I've never owned a vehicle that did have a self dimming mirror.
But I've never really wanted one. Sometimes I think the simpler solution to the problem, is the best, and the flip technology is fine with me.

Also, I've never needed any help being dim.

 

I agree with you guys. I have had auto dimming mirrors in different cars (even some with both auto-dimming wing mirrors) and they work great but it does not work for our Prius. That dang spoiler is right in the line of sight of the sensor. I actually prefer the regular manual day/night mirror for this generation Prius.

Not sure about the 4th gen hybrid but my bro-in-law just bought a 2018 Prius Prime Advanced and we drove it at night and that mirror works perfectly!! The sight line is low enough for the mirror to catch all the glare so it can dim.