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Discussion Starter · #1 ·
I've searched the forums for a while now and haven't seen this situation posted before. Hope someone has some ideas...

On my 2007 335i, all the sudden the driver's outside mirror seems "stuck" on dim. This is during daylight, power on or power off. I have no window tint on the car.

I sat in my car the other day and took pictures of both outside mirrors and the inside rearview mirror. You can see the differences - both the passenger and rearview are basically not dimmed, and then the driver's is dimmed, showing the distinctive green tinting.

No leaks or bubbles on it (electrochromic fluid) and these pictures were taken with the car power totally off. In fact, I've also removed the glass as a test, disconnecting the cable, and it stays dimmed.

Sure seems to me there's some sort of permanent bias now in this thing.
Any ideas or similar situations? I'd even take on some experimentation with powering up the glass with a power supply if someone has the pinout of the cabling.

Thanks
 

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· Breaking in the Pony
2019 Mustang GT / 2005 Toyota Tacoma
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There's two sensors, one a small round dot on the top center glass side, the other a square opening on the back towards the right side of the car.

With the car powered on during the daytime, alternate covering each for about 30 seconds at a time, first on the glass side (which should force mirror to lighten) and then on the back (which should force the mirror to darken). Alternate between the two a few times.

Does the tint of the inside mirror change? Does the "jammed" outside mirror darken/lighten in response to your covering the sensors in succession?
 

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^I was thinking maybe it was sensor issue too but then the opposite mirror and rear view would not operate properly.

There is a trigger inside the mirror assemble to switch auto dimming on and off. That's most likely bad.
 

· Breaking in the Pony
2019 Mustang GT / 2005 Toyota Tacoma
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6,447 Posts
It's less that I think it's a sensor issue than seeing if you can push a response at all.

My interior mirror went squirrelly last year while the exteriors continued to operate normally. I found that if I exercised the mirror over it's full range when it was balky, it would resume normal operation after 2 or 3 cycles, almost as if there was a threshold voltage that needed to be exceeded before the mirror would begin to respond, or as if there was a recalibration function going on.
 

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Discussion Starter · #5 ·
Thanks for the information folks. Sorry for the delay in responding.

I ran the test as suggested. With the power on (engine running actually), I tested using a flashlight, alternating sensors, 30 seconds per side (front/back of inside rearview).

Essentially, all three mirrors dim and un-dim as expected in response to the flashlight at the sensors.

With the light at the glass side of the rearview, all 3 dim.
With the light at the plastic (facing out) side, at the sensor, they all un-dim.

The outcome is that the driver's side outside mirror never dims or un-dims to the extent of the others.

I'm thinking it's just some permanent change to the electro-chemical nature of the fluid that is sandwiched inside the mirror. It just can't move to the extremes of its range like it did before.

Based on how much these things cost, I think I'm OK to live with it...

Thanks for the help!
 
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