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D3 - Lights Headlights, xenons, foglights. Everything outside the car that glows

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  #31  
Old 12th January 2020, 11:22 AM
ainarssems ainarssems is offline
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One of the boot lights was filled with water so took it off to drain and to try and reseal it. Measured voltage on LEDs while I was in there and they run at 1V when tail lights are on and 1.7V for brake light so need 1.8-2V LEDs. I did not have time to unsolder one and test the current. I see there was 5V mentioned before but using 5V LEDs they would be very dim.
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  #32  
Old 12th January 2020, 11:23 PM
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ivanhoe ivanhoe is offline
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The link I posted has the specs.
Those leds have been tested in the a8 lights and confirmed ok.
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  #33  
Old 10th October 2020, 09:38 PM
ainarssems ainarssems is offline
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I bough 500 LED pack from Amazon back in January https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1 , got the 500 pack as that was in UK available for next day delivery but did not get to change them until end of July. At this time more than half of LEDs were not working on the drivers side wing light so I changed all of the LEDs in that light. At the time noticed that couple of yellow indicator LEDs were not working as well so ordered 50 pack from the same seller on Amazon as the 50 pack was on UK stock for yellow. Unfortunately they sent me red ones not yellow. Got a refund from Amazon and they told me to keep red ones. I then bought yellow on ebay. https://www.ebay.co.uk/itm/5mm-Water...53.m2749.l2649

The red ones are indistinguishable from original on car when lit but they do not last. After about 3 weeks all on one PCB failed, I replaced again, after another 3 weeks another PCB failed, replaced again. 3 weeks later one PCB failed again. I have not measured the current, maybe they are driven a bit hard. I will test adding some 5W resistors to see how much resistance I can add without loosing brightness and see if it can help them last longer.

No problems with yellow ones yet but they are only on for short periods of time.
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  #34  
Old 7th November 2020, 03:21 PM
ainarssems ainarssems is offline
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Finally did some measurements.

It was 1.3mA going through each LED with tail lights on and 23mA with brake lights on so no wonder replacement LEDs kept blowing after 3-4 weeks of use as they are rated 20mA. There are 3x 4.7ohm resistors in parallel on one of PCBs which should be 1.6 ohm total, multimeter reads 2ohm. I added 2 and then 2+2 ohm in series in one of the wires and with extra 4ohm current went down to 20mA, I cannot notice any drop in brightness at least not in daylight, will check again when it gets dark.

I will leave it like this for now with a total of 5.6-6 ohm. But will get 3x22 ohm SMD resistors to go in place of original on PCB and replace if LEDs fail again and I need to go in there again. This would give about 7ohm total and bring the current a bit more down to give a bit of margin.
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1997 S8, reached end of life with gearbox failure
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  #35  
Old 8th November 2020, 05:09 PM
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ivanhoe ivanhoe is offline
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Thanks for updating. Interesting. 😎
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  #36  
Old 11th April 2021, 11:15 AM
ainarssems ainarssems is offline
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Quote:
Originally Posted by ainarssems View Post
Finally did some measurements.

It was 1.3mA going through each LED with tail lights on and 23mA with brake lights on so no wonder replacement LEDs kept blowing after 3-4 weeks of use as they are rated 20mA. There are 3x 4.7ohm resistors in parallel on one of PCBs which should be 1.6 ohm total, multimeter reads 2ohm. I added 2 and then 2+2 ohm in series in one of the wires and with extra 4ohm current went down to 20mA, I cannot notice any drop in brightness at least not in daylight, will check again when it gets dark.

I will leave it like this for now with a total of 5.6-6 ohm. But will get 3x22 ohm SMD resistors to go in place of original on PCB and replace if LEDs fail again and I need to go in there again. This would give about 7ohm total and bring the current a bit more down to give a bit of margin.
Well it failed again. They did last 5 months which is a wast improvement over 3 weeks they usually lasted without extra resistors. Colder weather have helped as well no doubt. Back to the drawing board, 3x 22 ohm SMD resistors ordered to go in which should get current down a bit more and hopefully last more than year.
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2006 A8 Sport 4.2TDI quattro SOLD,
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  #37  
Old 11th April 2021, 01:57 PM
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tonupkid tonupkid is offline
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Quote:
Originally Posted by ainarssems View Post
Well it failed again. They did last 5 months which is a wast improvement over 3 weeks they usually lasted without extra resistors. Colder weather have helped as well no doubt. Back to the drawing board, 3x 22 ohm SMD resistors ordered to go in which should get current down a bit more and hopefully last more than year.
If you can crack this and considering the number of D3's out there needing the fix You could make an income off fixing, or getting someone to fix, these.
And I guess your knoweledge will apply equally to other models and makes. Gold mine
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  #38  
Old 6th June 2022, 07:30 PM
Bushido Bushido is offline
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Did we please ever get a solution to this??

I cannot get me head around the 2nd price of replacements and new... Id sell the car on first. And that's saying something!!
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  #39  
Old 7th June 2022, 07:39 PM
ainarssems ainarssems is offline
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Last time I replaced them I also changed 3x SMD resistors on one of the PCBs for tail/brake lights from 4.7 ohm to 22 ohm this brought down amps to about 18mA per LED for the 20mA rated LEDs. This made them last, I sold car 8 months later and they were still working fine. The link to red LEDs I used on Amazon is in my previous posts and is still valid. Resistors that I used were from eBay, link is no longer valid but part number was SP123WJ0220T1E 22ohm, 3W. If you are using different LEDs you might need different value resistors.

For the indicator amber/yellow LEDs I got them on eBay, link is no longer working and I do not have part number. I did not have any issues with them after replacing first time so did not look into any details.
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  #40  
Old 5th July 2022, 09:52 PM
jonnypym123 jonnypym123 is offline
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Here was my no bench power supply method of telling the dodgy ones still present after soldering new indicator leds, get the wife to indicate whilst holding the boards on a tea tray, worked perfect quick soldering of the remaining 2 dead ones and it was sorted. Sealing the middle light clusters I used granville sealant. Just got to face it it's one of the things on the car that needs maintaining every few years
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