I could be crazy about this and I have tried searching to see if anyone else has the same issue.

Usually the rearview mirror will dim itself when someone has their headlights on behind me. I have noticed lately that if the car is close to me it seems to not work anymore. If cars are way behind me then it will dim to that "monochrome" look.

Should the mirror stay dimmed or does it undim a little when cars get closer?

 

the mirror will work better if you partially cover the sensor on the front with some electrical tape...try it with your finger next time someone is behind you.

 

Mine stays dimmed, if anything it dims more lol or my eyes are just fucking with me

 

Will try, thanks!

 

i've never noticed mine NOT dimming when cars are closer...

why would covering the sensor on the front help make it dimmer? i don't get it...

 

Im thinking its light overload on the sensor like when my camera went out of focus when we filmed a firework show. As soon as it got really bright the light sensor freaked out and caused the camera to shut down.

 

OK, tried the tape and nothing changed. Noticed the brightness of the rearview is the same as the side mirrors when someone is behind me.

Got to take the car in anyway since I have a weird rattle coming from the back of the car. Will have them check out the mirror at the same time.

I could be crazy.

 

Dealer is going to order me a new mirror. Hopefully will get it in a few days.

 

Q: How do Auto Dimming Mirrors work?
A: 1. A forward-facing sensor recognizes low ambient light levels and signals the mirror to begin looking for glare.

A: 2. A rearward-facing sensor then detects glare from the vehicles traveling behind you, sending voltage to the mirror's EC gel in proportion to the amount of glare detected.

A: 3. The mirror dims in proportion to the glare and then clears when the glare is no longer detected.

A: 4. The interior mirror's sensors and electronics control the dimming of the mirrors.

---by blocking the front-facing sensor, even in the daytime, it will make the mirror think there is a bright light shining in the rear-facing sensor....dimming the mirror.

--- by partially blocking the forward-facing sensor with a piece of electrical tape, it will make the mirror dim a lot more quickly.

 

Kinda-sorta.

The ambient light sensor is an on/off switch. If the sensor detects light then the mirror will not dim. If the sensor (based on some preset threshold) detects that it is dark outside then the mirror will dim when light strikes the mirror. The more light that hits the mirror, the more it dims.

Placing electrical tape partially over the sensor will just make the mirror dim earlier but will not affect the amount of dimming.

Tinted windows will affect the dimming as the tinted windows will reduce the amount of light hitting the mirror. There is a sensor on the mirror portion itself. Light needs to hit that section in order for the mirror to dim. If the light gets close and no longer hits that sensor (because of the way the mirror is adjusted) then no dimming will happen.

I can't think of a scenario where a mirror defect would cause the mirror to dim less when the sensor detects more light, but I guess it could be a really whack-o defect.

 

Everything is working well now with the new mirror. I have noticed that the new mirror is somewhat dim all the time. Has a very light monochrome look to it. Dims really well at night.

 

Good news. Did they say what the issue was?

 

No they did not say what the issue was. I think they just took my word since I only waited about an hour at the dealership. They also had to replace a velcro strap up in the headliner since I had a rattle in the back. Im sure that took a little time to replace.

I wouldnt doubt it if a mirror has failed before since Acura has been using this type of mirror for years. There is also a TSB out for defective mirrors with the compass. Maybe mine falls under that same TSB.

 

im not too sure they replaced it, most parts they do not keep at the dealership, they have to order them in, and usually takes atleast a few hours, or the next morning. maybe they just fixed something weird on the sensor? unless they had some lying around due to TSB

 

Few posts up I mentioned the dealer ordering a new mirror. They took about an hour the first morning to look at the mirror and fix the rattle in the headliner. They ordered the mirror which came in a few days later. Its a new mirror since the last one had a small scuff mark on the plastic. Where the scuff came from, who knows.