Howto: Upgrade to autodim/rain sensor mirror

MNShortBus

Member
Joined
May 6, 2012
Location
Minneapolis, MN, USA
TDI
2003 GTI, 2014 Allroad
I believe I have solved this mystery finally! My suspicion about the voltage dips on pin 1 appear to be correct and is definitely related to the signal to the wiper relay.

I used my phone camera to capture the IR light from the sensors (some phones have IR filters, luckily mine didn't). The sensors sending .6 volts are dead and do not emit any IR light. It looks like these IR LEDs simply wear out with age because the newer ones are working better. VW was nice enough to print a manufacture date on the back. A good sensor should send up 5V to the wiper relay and will lower the voltage according to the sensor detecting a change in IR light. This dip in voltage tells the wiper relay to turn the wipers on.

Now for the pics. Earlier it was mentioned that the LEDs appear to be missing from the sensor I took apart. They aren't missing and instead are EXTREMELY small.


Here is a dead sensor. Notice the lack of light.


Here is an almost dead sensor. This is the one from my car. Notice how only 4 LEDs are working and they are very dim.


Here is a working sensor. All 8 LEDs are working. I installed this sensor in my car and it was working even without the gel.



Hopefully this helps others with a dead sensor function on their cars. I can finally finish this mod after 3 years.
 

brnsgrbr

Veteran Member
Joined
Oct 13, 2009
Location
Washington State
TDI
2002 GOLF GTI converted to GTD
Subscribed as I too will be installing a unit from a R32. I bought off a wrecked car last year.


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putangspangler

New member
Joined
Mar 17, 2003
Make sure you test the sensor like I did above before installing. Don't waste a new rain sensor gel film on a bad sensor. ;)
I was finally able to find and test the one I pulled over a year ago. I have 8 strong LEDs, but have two questions.

First, what should I use to clean the old gel pad off of the sensor?

Second, I seem to have lost the plastic back to the sensor. How important is that?

Thanks,

Patrick
 

JettaTDIBlack

Veteran Member
Joined
Jul 7, 2016
Location
Brandon, FL
TDI
2002 Jetta TDI Automatic Sedan
What makes, models, and years are compatible with this mod? Meaning which cars can I look for in my local junk yard to pull parts from. Yesterday, I replaced the windshield in mine and I opted for the rain sensor version. Which is just a windshield with the mount for the mirror and nothing else.
 

RexNICO

Veteran Member
Joined
Sep 17, 2013
Location
South of Atlanta
TDI
2012 Q7
What makes, models, and years are compatible with this mod? Meaning which cars can I look for in my local junk yard to pull parts from. Yesterday, I replaced the windshield in mine and I opted for the rain sensor version. Which is just a windshield with the mount for the mirror and nothing else.
Some older MKIV GLX, but should be much easier to find the mirror in a B5/5.5 Passat.
 

brnsgrbr

Veteran Member
Joined
Oct 13, 2009
Location
Washington State
TDI
2002 GOLF GTI converted to GTD
MK4 R32. You will need the entire wiring assembly leading to the mirror, and sunroof, from the fuse panel and relays.


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VWfanatic

Well-known member
Joined
Mar 13, 2006
Location
Kansas City
TDI
Wife got it in Divorce
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