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Discussion Starter #1
Hello all. I've been lurking around this site for a couple of months, but this is my first post.

I picked up my 2003 325i (silver/black leather, PP, HS) on 9/27/02. The car is great, except for one (little?) problem. Within a couple of days of taking delivery, the rearview mirror became unusable. Whatever is inside it that gives it its day/night properties began shifting around, and the thing began to look like a lava lamp. I took it back to the dealer, who ordered a new mirror. The new mirror took a while to come in, and the original one just kept getting worse.

The new mirror was intalled last Friday, and by Saturday morning it was doing the same lava lamp trick. The car spent the whole day yesterday with the dealer techs, and they found nothing. The result: they ordered me another mirror. I'm thinking that it will be a lava lamp, too.

Any other '03s experiencing this?
 

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Traffic Surgeon
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smlewis said:
Hello all. I've been lurking around this site for a couple of months, but this is my first post.

I picked up my 2003 325i (silver/black leather, PP, HS) on 9/27/02. The car is great, except for one (little?) problem. Within a couple of days of taking delivery, the rearview mirror became unusable. Whatever is inside it that gives it its day/night properties began shifting around, and the thing began to look like a lava lamp. I took it back to the dealer, who ordered a new mirror. The new mirror took a while to come in, and the original one just kept getting worse.

The new mirror was intalled last Friday, and by Saturday morning it was doing the same lava lamp trick. The car spent the whole day yesterday with the dealer techs, and they found nothing. The result: they ordered me another mirror. I'm thinking that it will be a lava lamp, too.

Any other '03s experiencing this?
Sorry to hear that. Do you have any pix of exactly what it looks like? I am just curious since I have never heard of this before (obviously being a 2003, I probably wouldn't have).
 

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I'd suspect the light sensor causing the mirror to change from day to night mode and back. I think there may be two sensors but I am far from sure.
 

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Car Junkie
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Most of the time, the sensor for an electrochromic (auto-dimming) mirror is on the mirror itself. I've heard of malfunctioning units acting this way, but it's strange that you would get two defective mirrors in a row. Perhaps there's an electrical problem with the wiring harness leading to the mirror.
 

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Vegan, not Romulan
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As far as I know the auto dimming mirror works off a liquid crystal layer in the mirror. There are 2 light sensors on the mirror, one facing the front of the car, and one facing the rear. When the rear sensor has a brighter reading than the front sensor the electronics kick in to dim the mirror by applying a charge to the liquid crystal.

It sounds like the layer of liquid crystal is damaged so that the liquid is flowing freely instead of staying in place and waiting for an electrical signal to polarize it. That would explain the lava lamp effect. I have seen damaged laptop screens that look exactly like that.

Did the mirror sustain any kind of impact or pressure? Typically the liquid crystal is held in place between 2 sheets of very thin glass/plastic. The layers can be damaged by impact or force.
 

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Discussion Starter #6
Thanks for the responses! I'll try to take a picture tonight.

There's been no impact at all to either of the mirrors. One of the techs also mentioned impact. He said the only other time he'd seem such a problem was on X5 side view mirrors that had been whacked.
 

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Rest in peace, Coach
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Pull fuse # 24 in your glove compartment. That will PERMANENTLY set it to day time mode (cut power to the mirror).
 

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Discussion Starter #8
Sorry, I didn't find the time to take a picture of the lava lamp. I took the car in this morning, and they installed a new mirror for the 2nd time in the 4 weeks that I've had the car. On the drive home (less than 5 miles), the new mirror began to lava lamp, so the problem is getting worse.

The dealer is now "looking into it," and will let me know something later today.

Hack: my fuse box is showing 2 fuses for the mirror: 24 and 67. If I'm going to pull one, should I pull both?
 

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Rest in peace, Coach
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smlewis said:
Sorry, I didn't find the time to take a picture of the lava lamp. I took the car in this morning, and they installed a new mirror for the 2nd time in the 4 weeks that I've had the car. On the drive home (less than 5 miles), the new mirror began to lava lamp, so the problem is getting worse.

The dealer is now "looking into it," and will let me know something later today.

Hack: my fuse box is showing 2 fuses for the mirror: 24 and 67. If I'm going to pull one, should I pull both?
No. Fuse 67 also acts as the fuse for one of the brake subsystems (Either dynamic brakes or stability control) and fuse #24 is shared by the dimming mirror AND park distance control. Pulling fuse #24 will completely disable the mirror without affecting any of the safty systems.
 

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There and back again
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smlewis said:
The dealer is now "looking into it," and will let me know something later today.
See my "Picked up 325xiT; multiple problems" thread for something that might be related.
 
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