Auto-dimming Mirror Troubleshooting

benmarks

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2004 Jetta GLS Sedan Platinum Gray
I recently added a new windshield and connected the rain sensor and auto-dimming mirror to my MK4 Jetta. The rain-sensing wipers work great, but the mirror does not appear to dim. I double-checked all the wiring. The mirror is brand new but it has a slight bronze tint. Does that mean it is bad? I found a thread on another forum that seemed to indicate that was the case, but since it is brand new I am slightly skeptical. Does the mirror only need power, or is it controlled by something else other than its own light sensors?
 

RexNICO

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2011 Tiguan, 2011 Q7
Yes, the bronze or gold mirror coloring is indicative of a mirror going bad.

Assuming it is an OEM mirror, it should have a 6 pin rectangular connector, with 6 wire on the mirror side & (most likely) only 3 on the car side. It only needs ground and 12 volt, the 3rd wire should be the reverse trigger to defeat function when the car is in reverse.

I may have one if you’re interested.

Thanks
 

benmarks

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I ordered a 2nd mirror (new) but it still doesn't work. I guess it must be me. I tested power and ground, and the connector appears to be getting power. I should be able to activate it with a bright LED flashlight, correct? I am testing with the car engine on and in gear and with the lights on. This mod doesn't require anything to be changed in Vag-com does it? My rain sensor does work and I used the OEM wiring harness when I connected everything. I am running out of ideas.
 

RexNICO

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The mirror should activate if you provide a bright light from behind AND block or cover the front sensor. The mirror needs the front (facing) sensor to think it’s night time, while the one you see from the drivers seat sees a brighter light. Make sense!
 

benmarks

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Yeah, that's precisely how I was testing. I double-checked the wiring diagram. I get 12 volts on the pin that is the blue/black wire in the following diagram and nothing on the other 2 pins. This is what I am referencing:

http://forums.tdiclub.com/showthread.php?t=38714&page=10

How "bronze" is "bronze?" I noticed the "new" 2nd mirror was scotch-taped shut when I got it and it has a slight bronze tint too. Is some tint normal?
 

benmarks

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2004 Jetta GLS Sedan Platinum Gray
Maybe my harness is wrong? I should admit that I am not very good at reading wiring diagrams but I did not modify this. It is how the part shipped to me. Here are two photos. In the first photo, the left-most brown/blue wire is what has 12 volts. In the second photo, that row of wires corresponds to the top row of holes.



 

benmarks

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A side note... are there multiple versions of the black auto-dimming mirror? I have 3B0857511H01C. I didn't think so, but in this thread, the photos show a mirror with five wires in the base and mine only has four: https://uk-mkivs.net/topic/184364-mkiv-auto-dimming-side-mirrors/

I know there was a W8 version with a power button and red lights like the W8 dome light, but since the W8 never came with a black interior, I don't think a black version of that rear view mirror exists.

Before attaching them, I was planning on creating the ultimate power folding heated memory auto-dimming side view mirrors with puddle lights, but I guess I can't if I don't have five wires right?
 

benmarks

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Actually, maybe there are two mirrors. I have 3B0857511H01C which has 4 wires but after an hour of searching, I just found a second part number 3B0857511C01C. This doesn't show up on the following site if you search via car model, you have to know the exact part number to find it, which I found elsewhere. The 2nd photo here shows what I am describing: https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/mirror/3b0857511c01c/

If you look very closely at the 2nd photo, it looks like there are two wires (for a total of 5) where on mine there is only one (for a total of 4 [I made sure to verify the orientation based on the patterns in the plastic connector.])
 

RexNICO

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In my exp, any gold or bronze coloring meant the mirror had no value.


As for the different part numbers, it could be a few different reasons, as the black mirror came with and without the downward lights is the first that comes to mind. I'm 99% sure there was one with the downward lights.



In my exp of disassembling multiple VW/Audi auto-dim mirrors for different conversions, I never came across any with different power needs. To test them, I built a little 12v power supply using camping lantern batteries.


As for the mirror side of the connection, I've almost always seen 5 or 6 wires, which run to the PC board inside the mirror. So, I don't think the # of wires on the mirror side matter much.


Do you know if your rain mount uses the larger diameter ball or the smaller?
 

RexNICO

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Found these notes as well
Car side connector Pin #1 and Pin #2
Pin #1 is a black wire with a blue stripe (power), and Pin #2 is a brown wire (ground).

Mirror connector Pin’s #1 and #2.
Pin #1 is power (white wire) and Pin #2 is ground (black wire)
 

benmarks

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That pin info was super helpful. It was also helpful that I accidentally purchased two harnesses last year when I originally planned to do this. I just looked at the connector on the other harness since the numbers were too small to read off of the one dangling in my car, and it looks like pins 1 and 3 are reversed in the one in my car. The wire in pin 3 was providing 12 volts. I practiced on my extra harness, but I haven't tried swapping the wires in the car yet.

As far as mirrors go, I have found out a few things. There was a "J" version that came with down-firing red lights and a power button but from what I understand, it never came in black because it was primarily a part in the W8 (similar to the W8 dome light.) There may have been another version that had a power button and did come I black, but it is an oval shape, didn't have down-firing lights and appears to have only come in some Polos. The ones I had been using while testing in this thread were the "H" revision. I just purchased a "C" revision for testing too, not because I thought my two H's were broken but because the C would be preferable to the H due to the of the number of wires in the mirror side of things. The H only has four wires, which means I cannot use it to hook up auto-dimming sideview mirrors. The C has five wires which is what is needed to connect the sideview mirrors. There were other revisions too, but these all seem to be the most common ones. Most people would probably be fine with the four wire version, but I want the auto-dimming Audi glass. I have yet to find a black mirror for the round rain sensor/mount with down-firing lights. I do see them for the rectangular rain sensor. If there is a black one with down-firing likes for my application, I would be curious to know the part number. I tried looking for one a few days ago and could not find one that would work with the round rain sensor/mount.

I didn't know about different rain sensor diameters, so I am not sure what I have. The one I have seems to fit perfectly in the round mirror mount (I replaced my windshield to complete this mod.) What is the difference between the two, other than diameter?
 

benmarks

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Oh thanks goodness, IT WORKS! It ended up being that the OEM harness had pins 1 and 3 swapped. Having an old used 2nd harness helped because I could figure out how to disassemble the connector without breaking it. Thanks to all for the help!
 

RexNICO

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My diameter question was on the ball/socket side, not the rain sensor side. Where it swivels in the back of the mirror body.
 

benmarks

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Ah ok. Now that I have everything working, I think I might actually order a grey W8 mirror and paint it black so that I can have both the power override button and the down-firing LED's. I bought a cheap dome light on which to practice and to see if I can find the right paint. However, I can't seem to determine from photos whether the W8 mirror version has the 5 wires in its connector needed to support auto-dimming sideview mirrors. Does anyone happen to know?
 

RexNICO

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If you have the W8 overhead console, I wouldn't be too worried about a mirror with downward lights, I'd go after a more feature filled mirror.


Audi A4/A6 (B5 & C5 chassis) with a compass display, I like the squarish body on these.


Audi A4/A6 (B6/7 & C6 chassis) with a hidden compass, I actually (painted &) swapped one of these on to a rain mount base. I liked it, it was cool, but the rounder body isn't my favorite.


VW Passat (B6 I think) no compass, but neater/newer square design, no additional features.


Saab/GM various years, has both compass and homelink functions, more work and a blue compass display, but more features.


Almost all of these can be swapped into the ball of your rain mount, if your rain mount is the later style with the larger diameter ball.


As for painting them, it looks okay and is acceptable for normal use, but give the amount of time/money you're putting into the comfort creature mods you've been doing, I'm not sure you'd be happy long term.


It's worth mentioning that almost all of these mirrors use 1 of 2 different connectors on the PC Board and you can re-pin the other end to use the rectangular 6 pin VW/Audi you mentioned above.



I've had my hands on and taken apart MANY mirrors over the last few years, so feel free to ask any questions.


Hope you can get the function and look you want from this mod.
 

benmarks

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I don't have a W8 dome light yet. I have yet to find a black one (rare TMTuning or super rare Volkswagen Individual.) I am trying to see if I can find a place that can make a one-off by painting and then laser etching it. If I did have a W8 dome light, I would want a mirror with 6 wires, correct? Wires 1, 2 and 3 would be for power, ground and brake signal. Wires 4 and 5 would be for the auto-dimming side mirror glass (which I purchased.) And, wire 6 would connect to the dome light from what I understand and the dome light itself would toggle the auto-dimming function if the red lights in the dome light are turned on. Does this sound correct? If that is the case, I'd want an Audi mirror that auto-dims and has a compass, but no power button.

I don't think I like the ones with a power button also because the persistent green LED when dimming is activated just seems so out of place. Maybe there are other greens in an Audi, I don't know, but a lone green LED in our cars seems odd.
 

RexNICO

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I don't have a W8 dome light yet. I have yet to find a black one (rare TMTuning or super rare Volkswagen Individual.) I am trying to see if I can find a place that can make a one-off by painting and then laser etching it. If I did have a W8 dome light, I would want a mirror with 6 wires, correct? Wires 1, 2 and 3 would be for power, ground and brake signal. Wires 4 and 5 would be for the auto-dimming side mirror glass (which I purchased.) And, wire 6 would connect to the dome light from what I understand and the dome light itself would toggle the auto-dimming function if the red lights in the dome light are turned on. Does this sound correct? If that is the case, I'd want an Audi mirror that auto-dims and has a compass, but no power button.

I don't think I like the ones with a power button also because the persistent green LED when dimming is activated just seems so out of place. Maybe there are other greens in an Audi, I don't know, but a lone green LED in our cars seems odd.



Sorry, I misunderstood, I thought you already had the W8 overhead console.


I can't say for sure if you need 2 wires coming out of the mirror to activate side auto-dimming glass (directly/individually), or if it's 1 wire that goes to a relay. As much as I would really like to have auto-dimming side view I never dug into it that far. My "idea" was to operate them manually with a dash mounted switch. I also wanted to re-wire the side mirror defrost to a timed switch. All plans that have never made it past the "day dreamer" phase.


As for the downward red ambient light, I thought (mirror or dome light) they were always on, you just can't see them unless it's dark. Maybe they toggle off when the dome light illuminates, I'll have to see if I can test/re-create in my Brothers A6/C5.


I agree, the "power light" seems counter to the whole idea. It's no as bad as the manually operated units in the mid-90's Lexus SC400 I had, but still seems awkward.


If you needs some parts, pieces to test/play with, let me know I have boxes and boxes of parts & pieces.
 
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