# Rear Light Assembly Ground Fault ~ Non-OEM Repair



## TT-driver

Various topics appeared on this forum already regarding the rear light cluster packing up completely. 
As we've seen in the other topics, it's mostly due to a corroded earth connector in the plug/socket.

In my case however the connectors were still reasonably clean and no signs of overheating. Hopefully I now have a solution to the problem as it appeared in my September 2006 TT.

First of all, I noticed that the resistance from plug to the car battery was 0.6 Ohm and not 0.0 Ohm as should be the case. The root cause appeared to be at the other end of the wire, in the boot corner of the car. I disconnected it, used a fine grid sand paper to clean the bolt, the 'O' connector and the body work. Reinstalled the connector and result: 0.0 Ohm now. No resistance any more from plug 'all the way' to the battery.

Next point of attention: the actual connection from plug onto the bulb holder. Two issues here:

1) the metal used as wire on the holder corrodes. This corrosion turns into electrical resistance. Current and resistance create heat. From there things just go pear shaped.

2) the actual connector for earth imho is too small really. When brake lights, indicator lights and reverse light are on all at the same time, we're looking at 2*21 + 2*16 + 1*16 Watts = 90 Watts, close to 7A. That is a serious current.

I think this is a bit of a design flaw and replacing the bulb holder will only help if Audi uses a more suitable metal for the current ones. I don't know if they do.

This week I thought hard of a solution that did not involve running off to Audi and that had to be mostly reversible just in case it wouldn't work out. I think I've got it now.

First I looked for a suitable point for creating an additional earth connector, without the need of drilling a hole in the body. Found it:










This is one of the 4 bolts holding the beam behind the rear bumper on to the bodywork. I connected a 50cm wire with a soldered O ring to it to this point. Applied some wax afterwards, protecting the bolt and connector from dirt and water.

Next I looked up a suitable place to drill a hole in the bulb holder plate:










I cleaned the 'wire' locally a bit (after taking the picture) and put a screw in with washers at both sides:










And the other side:










Now the mounting on the car. Used a wing nut so I can undo the additional connector (and the whole light unit for that matter) without the need for any other tools than those supplied with the car. Here you see the light unit turned upside down, with the additional earthing connector connected.










The location of the connector was chosen in such a way that the likely hood of it getting into contact with water is quite small. Still after making the connection, I applied again a bit of wax.

So that's it: an additional earth connector to the light unit. It's installed on the right hand side now. When comparing the units left and right, I can see that the intensity of the rear lights and the reverse lights is more stable with the indicator switched on than on the left hand side. A clear sign that on the left, the unit is still suffering from a poor earth connection. Hope this solution will prove itself for years to come. Took about an hour to install and a couple of hours of thinking. If it doesn't work, it's all reversible except for the 3mm hole in the bulb holder. But that holder would have to be replaced anyhow in case this fix doesn't work long term.

_For the sake of completeness: this is the right hand side unit on a left hand drive car. When applying the same 'upgrade' to your own car, ensure that it's the correct 'wire' in the unit that you're connecting to earth. Otherwise you'll create a short circuit. And at all at own risk. Feedback is welcome._

_Edit: restored the links of the pictures. Thanks to Brittan for copying them for the knowledge base_
_Edit2: restored the links once more. Pictures are now hosted by the forum itself_


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## igotone

Excellent - should be very helpful as this seems to be a common issue.


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## wja96

That's a really useful post. Definitely should be sticked or added to the KB.

Thanks for posting this.


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## IC_HOTT

cheers man, very informative and useful :wink:


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## Sifu-TT

Nice, just had mine repaired at the dealer under warranty after buying the car a week ago.


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## peter-ss

I too now have this issue - My outer offside light has become intermittent and on inspection I have very slight distortion of the plastic around the earth pin.

For now, I have just cleaned up the connector but will be carrying out your modification in the very near future.

The only thing that intrigues me is why a dodgy earth connection manifests itself in just the one bulb going out viewtopic.php?f=19&t=162142&hilit=rear+light+fault. I'm guessing that the reason you don't get the Ford Escort style disco lights is due to the lights being electronically controlled, rather than all being physically connected together, so they can't earth through each other.

I drew the layout of the rear light cluster and the pinout of the connector (offside) and, interestingly found that both indicators are fed separately as are the two Brake/Tail lights - Maybe this is for the bulb failure warning system?





Thanks for the write up.


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## ZephyR2

These were the kind of problems I was dealing with on old Fiats and Alphas 20 years ago. How can a premium car manufacturer like Audi still be getting it wrong? 
FFS :x


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## peter-ss

I have now carried out the supplementary earth modification and the difference in my rear lights is visible.

Pre modification, with the engine running, the car in reverse, the brake lights on and the indicator flashing the voltage on my reverse light was dipping to just over 10V and you could see the intensity alter as the indicator flashed.

Post modification the voltage only dips to 12v and the intensity of the reverse light doesn't seem to alter at all.

I now feel a bit happier knowing that my rear light fittings aren't likely to melt!


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## TT-driver

peter-ss said:


> Pre modification, with the engine running, the car in reverse, the brake lights on and the indicator flashing the voltage on my reverse light was dipping to just over 10V and you could see the intensity alter as the indicator flashed.
> 
> Post modification the voltage only dips to 12v and the intensity of the reverse light doesn't seem to alter at all.


I did the exact same test afterwards.



peter-ss said:


> I'm guessing that the reason you don't get the Ford Escort style disco lights is due to the lights being electronically controlled, rather than all being physically connected together, so they can't earth through each other.


It's either that, or the drivers inside the control unit that provides power to the various bulbs (based on a canbus signal) can't provide enough current for two bulbs. 
For the rear lights/break lights the individual connectors are also there for switching on just 1 bulb in case of using the parking light: indicator to one side, ignition off.

Perhaps if one of the bulbs is actually broken, the VAGCOM may tell exactly which one it is.

By the way: the earth connectors inside the boot space had a bit of resistance too on mine. They are in the corners close the the light cluster, underneath the carpet.


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## peter-ss

TT-driver said:


> For the rear lights/break lights the individual connectors are also there for switching on just 1 bulb in case of using the parking light: indicator to one side, ignition off.


I hadn't noticed that this was the case and it explains why they're not just paralleled up.

I wonder if there's a reason for the indicators being fed separately too?


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## TT-driver

peter-ss said:


> I wonder if there's a reason for the indicators being fed separately too?


I looked at the wiring diagram and the J519 unit descriptions. But I can't find the reason...


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## V11TNO

I have just carried out this modification and its worked a treat!  

Thankyou very much for the 'How to'


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## UMZ

I'm no technician and although this guide seems spot on I went to my local Audi garage in Stockport. They wanted £120 to resolve 'the known issue'. I got them down to £80 as they could clearly see I've been through 2 new rear bulb cluster that have been burnt through because of the earthing issue. For this they will replace the cluster £27rrp, change the pin £5 RRP, solder in fix the earthing issue plus labour. I think that's reasonable but still pissed off. Been stopped 3 time by the police in 1week due to no rear indicator and the fog this morning. Annoying.


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## Stolberg

Hi, I have had a go at doing this earth bipass mod, as I too was getting the intermittent tail light failure on my 08 TT.
I had tried the cleaning of spades and connectors to no avail.
My question is: I have placed the additional earth connector to a bolt on the chassis/bumper (metal) adjacent to the light fitting, rather than down and underneath the car like shown in your photographs. 
Will this work? The lights are working. Is this a worthy earth point???
If you remove the light cluster the bolt can be seen nearest to the side of the car. It has made for a shorter earth wire from cluster to earth point. I also used male bullet/female terminals to allow easy disconnect when changing a bulb, rather than a wing nut. 
Thanks for this mod... I was quoted 120 just to look at the problem!!!


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## TT-driver

Hi and welcome, as I see this is your first post here on the TT forum 

I'm not exactly sure which bolt you are referring to (a picture would help), but any bolt that makes proper connection to the metal of the body itself should provide for a proper earth connection. As long as the earth point doesn't get wet it should be OK for a long time.


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## Stolberg

Yes my first post, but have been visiting the forum since buying my TT last year. It has saved me cash and put my mind at rest on many occasion 

The bolt point I used appears to be one of the fixing points of the bumper. I cleaned the points before fixing but did not apply grease or wax to protect the points. What products would you recommend?

After doing the wiring, I had a look underneath the car and wasn't sure which of the two bolts I could have wired to. I would have thought the chances of water getting at the earth would be greater here?

Fingers crossed the point I have earthed to will have done the job and I won't hear that annoying fault signal again. If it does work... a picture may be a good add on to this how to. You would have to pardon my novice wiring skills though! 
Thanks for the feedback.


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## TT-driver

As long as there is proper metal contact towards the body, it'll be OK. Reason why I used the bumper frame bolt is that I didn't need to damage any paint, plus I wouldn't be connecting to aluminium. Aluminium combined with another metal can cause electrolytic corrosion, something that you'd want to avoid when it comes to an earth connection.

For protecting I'd use a spray on anti corrosion wax, just like the one they use nowadays to protect the body work from rusting on the inner side. I think the bumper bolts are high enough behind the bumper to stop them from catching dirt and mud from the rear wheels. A spray of wax will take care of protection for many years to come.


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## mwad

Guys, what is the usual fault ?


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## UMZ

Hi guys got my light sorted from Audi. They replaced the bulb holder the pin connector faulty wiring,a bulb and the earthing issue for £114. All ok and the work looks decent and clean.


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## Stolberg

Sporadic tail light failure message on start-up, drive a mile or so, press the break, signal disappears and tail light comes back on again. Amassive pain!


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## mwad

Stolberg said:


> Sporadic tail light failure message on start-up, drive a mile or so, press the break, signal disappears and tail light comes back on again. Amassive pain!


Damn........

Started getting this on Monday.......


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## Stolberg

It is really easy to do (the OEM repair), as long as you have right tools and components.
Took me half an hour to do.
You'll need:
Wire strippers, Wire cutters, Drill, Connector Crimper Tool (I used this rather than soldering iron), Electrical Tape, Thick 1m length of Earth wire depending on whether you are attaching to the bolt under the car or the bumper bracket next to the light fitting, wax or grease to protect earth connections from water.
1-off Male and 1-off female bullet connector - So you can detach earth wire when removing light cluster in future. (wing nut is another option as per top of this feed).
2-off connectors. The connector needs to be big enough to fit over the bolt you are connecting to (on car and bolt fitted to light fitting).
4-off washers and one nut and bolt. The smaller the better. I will try and take a picture in the next day or so to show how mine looks.
Trust me, I am a real novice with this sort of thing, but it is very simple to do.


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## Philplop

I did this yesterday. Now I've noticed that my innermost rear indicator bulbs don't work (this may have been the case before the fix, though) and my DIS is saying the rear fog isn't working. Jesus!


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## Stolberg

Nightmare. Did you put the connect to underneath the car or next to the light cluster/bumper bracket?

I guess you cleaned up the area you connected to, so that it was metal to metal (no paint or muck in between). And you placed the connector inside the light to the outer most metal wire run as per the pictures above?

[smiley=bigcry.gif]


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## TT-driver

Both inner indicators giving up seems too much of an coincidence. Try the rear lights again without the additional earth connectors, check the bulbs and check how they sit in the bulb holder.

I don't see a connection with the fog light. Perhaps it is broken?


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## Philplop

I actually fed it through into the boot and used the earth point in the rear corner, which I think is where the rear lights earth. I cleaned the contacts.

It's definitely the right 'wire' on the light, as I traced it myself before checking this how-to.

The new earthing has noticeably improved the light brightness, as I tried with and without the new earthing. Tested the indicators with and without too, with no luck.

I thought that the fog light may be unrelated, just seemed a big coincidence. I just haven't had a chance to check yet.

Thanks for the help and the initial how to.


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## TT-driver

So you've done the right thing then, lights are brighter so we're sure the earth connection is working.
You didn't accidentally forgot to re-attach the fog-light earth connector? I'd expect that one to be shared with the rear light units.


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## ChillOut

Greetings from Luxembourg!

The DIS bulb failure warning has popup a couple of times the last months, however only for a few seconds after I start up the engine and maneuver the car in the garage (most likely it comes up when I engage/disengage reverse gear in combination with the brakes).

So, after connecting VCDS the following fault code has been recorded:

Address 09: Cent. Elect. Labels: 8P0-907-279-30-H.lbl
Part No SW: 8P0 907 279 K HW: 8P0 907 279 K
Component: Bordnetz-SG H54 2501 
Revision: 00H54000 Serial number: 00000007227823
Coding: 01040E8280141C00471800001800000000095E075C210802000000000000
Shop #: WSC 01236 785 00200
VCID: 458AB0230C23B836E81-8010

Subsystem 1 - Part No: 8J1 955 119 Labels: 1KX-955-119.CLB
Component: Wischer AU354 H07 0060 
Coding: 00064784
Shop #: WSC 01236

1 Fault Found:
00984 - Left Tail Light (M4) 
012 - Electrical Fault in Circuit - Intermittent
Freeze Frame:
Fault Status: 00101100
Fault Priority: 2
Fault Frequency: 3
Reset counter: 177
Mileage: 34372 km
Time Indication: 0
Date: 2013.12.09
Time: 09:58:00

Freeze Frame:
ON
Voltage: 14.30 V
OFF
ON
OFF
OFF
OFF

From the symptoms I suppose that I have to do the modification suggested and avoid of course Audi stealers. My questions is the following: should I do this for the left rear unit (as per VCDS fault code), or the rear unit (as per the guidance in the first page), or even in both units???? The wheel is on the left side 

Thanks a lot for your help!


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## TT-driver

Each unit has its own earth connector. So with yours the left one needs to be fixed. I'd fix the right side too as most likely that one will fail when it's cold and wet, if you see what I mean.


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## VirtuallyReal

I had this fault on the DIS today, and i would like to try the non OEM repair, but the pictures on the guide are gone. I know is an ancient post but the issue seems to be alive and kicking...

Does anyone have the pictures?

Since this is a common occurrence on MK2 TT, maybe a DIY on the KB would be a good idea


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## peter-ss

The guide is in the knowledgebase, complete with picures (I dont know why they're not showing in this thread though).

Sent from AutoGuide.com App


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## TT-driver

It seems imageshack.us deleted them. :x

Restored them, now pointing to the location where Brittan saved them


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## brittan

TT-driver said:


> Restored them, now pointing to the location where Brittan saved them


 [smiley=thumbsup.gif]

Yes, I've had problems with imageshack and deletion of photos. It took a lot of time to find, re-host and restore the correct pictures. 
Originally I put the KB pictures on imageshack to make their locations distinct from my photos in my photobucket account, but now I simply run 2 photobucket accounts.


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## VirtuallyReal

Thanks guys!


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## VirtuallyReal

peter-ss said:


> The guide is in the knowledgebase, complete with picures (I dont know why they're not showing in this thread though).
> 
> Sent from AutoGuide.com App


I checked the KB prior to posting on this thread and couldn't find it.

With the pics you restored on this post i'm good to go, thanks!


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## Ownen

Can you buy the connector and the pins that fit into it from the dealers?
Does anybody have the part numbers for these?


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## TT-driver

The connectors and pins are available separately through the dealers according to various posts on various forums. I'm afraid I don't have the part numbers though.


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## Ivandobskey

Just had the connectors and wiring looms replaced under warranty on my 2.0 tfsi. Fingers crossed it's finally sorted!


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## psycho29TT

Hi guys!

I have a small doubt, and this is regarding the original cable. Should it remain the same way it is now? Just add the additional earth wire and I'm ready to go, right?

Thanks for the help, I think this will be my life saver!


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## peter-ss

Yes that's right, the original wiring remains the same.

Effectively the original earth wire and the supplementary earth wire are in parallel.


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## psycho29TT

peter-ss said:


> Yes that's right, the original wiring remains the same.
> 
> Effectively the original earth wire and the supplementary earth wire are in parallel.


Thank you for your response @peter-ss. My care is LHD and my problem comes on my left side, so I'm kind of afraid to screw things up as per this message on the OP

"For the sake of completeness: this is the right hand side unit on a left hand drive car. When applying the same 'upgrade' to your own car, ensure that it's the correct 'wire' in the unit that you're connecting to earth. Otherwise you'll create a short circuit. And at all at own risk. Feedback is welcome."

Also, it is recommended to do this on both sides then? I've also read from other experiences that this will get your light brighter, and I would like to keep my lights equal, so.... Have you done this to both sides or it's not really worth the trouble to do the non faulty side as well?

Thanks again for the help!


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## TT-driver

Guess who's here? :wink:

My reason for typing this
_
"For the sake of completeness: this is the right hand side unit on a left hand drive car. When applying the same 'upgrade' to your own car, ensure that it's the correct 'wire' in the unit that you're connecting to earth. Otherwise you'll create a short circuit. And at all at own risk. Feedback is welcome._

is that I have a LHD just like yourself. I'm not in a position where I can check all ins en outs on RHD cars. Most things are the same, some are surprisingly different. Peter-ss did great work on working out the details for RHD cars and turning this topic into an article for the TT owners magazine. As far as I'm aware it all turned out to be exactly the same.
However as I cannot foresee the skills of anyone reading this topic I had to put in the usual warnings. Come to think of that, the internet if full of far more stupid things to do that don't come with a warning.

Anyhow, do try this yourself (that's an encouragement  ) and do pay attention that you're indeed adding an additional earth wire to the earth wire in the unit. The earth wire in the loom is brown, so follow that lead and if you have some measurement equipment you can be a 1000% sure if 100% is not enough.

I do recommend doing both sides. It'll keep the brightness of the bulbs the same and when done right you can put this whole issue behind you for a long time. Next time you see a bulb warning, it'll probably be indeed a broken bulb and not some vague issue in a socket. 

*Edit:* Time flies. It's almost 3 years since I applied this fix. My light units are still working fine. 8)


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## psycho29TT

TT-driver said:


> Guess who's here? :wink:


Thank you, I was actually waiting for you to appear TT-driver!!!!

So, basically, and please don't think I'm a retard... (maybe I am!, just don't say it!)










Arrow on the pictures would be showing ground, am I correct? On the first picture, regardless the side of the lamp, that would be the point to drill the hole, and use the new ground?

Thanks again!


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## TT-driver

:lol:

Yup spot on sir!


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## TT-driver

Someone was kind enough to youtube the fix. It may help others too:


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## California3.2Quattro

Just wanted to thank you guys for this thread. My right rear light code was popping up and I discovered what the problem was here.

I sprayed Deoxit Gold into both male and female housings for the right rear light connection and the light has been fine since. (Though I did see the corrosion around the problem prong like the rest of you.)

It's only been a few weeks however, so we'll see if the Deoxit stands up long term. If not, it's nice to know how to perform the permanent grounding fix.

Incredible that Audi doesn't fix this for free. It's clearly a common issue and shouldn't be happening on a high end car.


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## TT-driver

You're welcome


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## migzy_1

just out of interest has anyone contacted audi HQ about this issue, I would of thought with enough people having the same problem they should issue a recall

if not a quick poll to see how many tt forum users have had it

cheers

migzy


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## TT-driver

Fair question. I think the answer would be no. At least I can't remember seeing a post that all was repaired free of charge and that the customer was provided with a gift to compensate for the inconvenience. :lol:

It also wasn't my intention of this topic in the first place. Sometimes you have to work around Audi instead of with Audi. I feel this rear light issue is such an occasion.

Please do feel free to start a new topic with a poll regarding the earthing issue of the rear light. I'd prefer keeping this topic focussed on the workaround itself. I always keep an eye on this one when it pops up again in order to see if more assistance is required and so on.


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## imac

Hi All, I am about to fix this problem on my 2007 TT in Australia.
I have bought the new left & right housings and new connectors and it comes with some wires in the kit. Does anyone have instructions on how/what needs doing to the wiring using the OEM products?


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## migzy_1

i've been getting the dreaded brake light failure, took the housing apart but all the contacts are spotless, all the bulbs are ok

any ideas or could it be a hard to find electrical gremlin

ta
migzy


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## brittan

migzy_1 said:


> i've been getting the dreaded brake light failure, took the housing apart but all the contacts are spotless, all the bulbs are ok
> 
> any ideas or could it be a hard to find electrical gremlin
> 
> ta
> migzy


Could be the bulb itself. Try swapping them brake light ones side to side and see if the failure warning follows.


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## migzy_1

great idea i'll give it a go


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## TT-driver

imac said:


> Hi All, I am about to fix this problem on my 2007 TT in Australia.
> I have bought the new left & right housings and new connectors and it comes with some wires in the kit. Does anyone have instructions on how/what needs doing to the wiring using the OEM products?


Hi and welcome!

Complete wire looms? If that's the case then you'll have to replace the wire loom and probably assemble the connector once the wire is pulled through the hole behind the light unit. The wires are colour coded, so its rebuild following the original, I'd guess.


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## imac

Thanks for the welcome Driver,

I bought the 2 light housings, 2 connectors, new lamps and the connectors came with 6 new yellow wires with sockets crimped on both ends.
I am assuming these are to replace the burnt sockets and splice into the old brown ground wire.

My main question would be, do I need to do the described Mod on the new housings to stop this from re-occurring? Or have these new light housings been fixed to remove the faulty design?
The ground pin on the new housings look the same as the old ones to me except they are they still clean.


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## brittan

The yellow wires are known as repair wires so each one can replace two in-connector sockets and be spliced into the existing loom. You'll need something small and flat at the end to release the tags to get the existing sockets out of the connector. I use a very small watch maker's screwdriver.

Audi has never acknowledged the earth problem and no re-design has been done. I'd advise doing TT-Driver's extra earth mod while you have the lights in bits.


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## tttony

imac, you probably don't want to hear this, but if you are going to add the new additional earth wires anyway, you didn't need to buy the new bulb housings, connectors and wires.


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## TT-driver

tttony said:


> imac, you probably don't want to hear this, but if you are going to add the new additional earth wires anyway, you didn't need to buy the new bulb housings, connectors and wires.


Yup. That's why I started this topic in the first place: how to avoid paying Audi twice for the same [email protected]


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## TT-driver

imac said:


> Thanks for the welcome Driver,
> 
> I bought the 2 light housings, 2 connectors, new lamps and the connectors came with 6 new yellow wires with sockets crimped on both ends.
> I am assuming these are to replace the burnt sockets and splice into the old brown ground wire.
> 
> My main question would be, do I need to do the described Mod on the new housings to stop this from re-occurring? Or have these new light housings been fixed to remove the faulty design?
> The ground pin on the new housings look the same as the old ones to me except they are they still clean.


Given the stuff you've bought, you can now opt for the OEM repair. Replace the burned pin in the socket and install the new bulb holders. My suggested repair is the bushmen repair using stuff from the local hardware store. Now should you install the additional wires? Well apparently down under the climate circumstances do trigger the same fault. You could try and install all goodies plus using some sort of grease to protect the connectors from oxidising. And then hope for the best. Or install the additional wire while your at it. And since you'll have to cut into the original wire anyway, I'd connect the additional wire to the original wire and effectively only doubling the earth connector on the bulb holder. Takes less effort. Do solder the connections. Don't use crimp tools or other methods. Up to you.


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## Freebooter

Just suffered all the same problems, but I am really surprised to get this in a 2 year old car. Both pin and socket are well burnt. I have done the mod and now have working lights again, pending Audi replacing the parts under warranty. It's just that driving here in Johannesburg without the right hand indicator working is an open invitation to be rear-ended!


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## California3.2Quattro

Spraying the connectors with Deoxit Gold is still holding up for me a month later. But the fix here is great should I need it down the road.


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## imac

Thanks Driver,

I will replace the burnt bits. 
Do you think the original problem is caused by the earth pin connection or is it caused by a "not so good" earth connection to the chassis?
If the original earth point is good, do you agree that adding another wire from the housing and splicing into the existing brown wire will add another path to ground will be a good fix? Then no need for another grounding point?

Cheers.


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## TT-driver

you're welcome.

The only reason why I used different earth points is because I wanted to avoid cutting into the original wires. You could double check the connection between the wires and the body. The brown wires are connected to the body quite close to the light units, underneath the boot carpet. You may need to remove the Styrofoam inserts. A bit of sand paper on both the body and the connector and it should be 100%.

The main issue is indeed the overloaded pin in the socket. Bypass that pin and the problem should be solved for a long time to come. Like said earlier: since you have to splice the wire anyway, by all means start the bypass from there. It's easier than undoing the bumper bolts and starting a new earth connection from there.


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## psycho29TT

I just wanted to thank you @TT-driver for your help. I had to do your repair and it worked just fine! I never had the problem again.

Sometimes I get the message from the front turn signals, so I activate them 2 times and it goes away, but weird....
Also my DRL changes intensity from lets say 100% to 90% when I move the steering wheel. I know the guy that did the fix for me, didn't use the car chassis for the fix, but the original mass point, so maybe this is what's causing the problem?

Thx again!!!!


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## TT-driver

You're welcome. I'm glad this fix is helping so many fellow TT owners.

The front light units have their own mass connectors. They can start playing up too. I found a bit of corrosion a couple of years ago between the connector and the sill on the earth connectors close to where the gearbox sits. A spanner and some sandpaper is required to clean them. A bit of anti rust spray will protect them from rusting any time soon again. I'm not 100% sure though if those earth points are the points for the head lights too. Checking them won't do any harm though. If I recall correctly another forum member managed to fix one of his front bulb error messages by checking those connectors.


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## WallaceTech

is this earth wire ok to use?

http://www.diy.com/departments/tower-gr ... 999_BQ.prd

or would this be better?

http://www.halfords.com/technology/car- ... h-cable-1m


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## Hoggy

WallaceTech said:


> is this earth wire ok to use?
> 
> http://www.diy.com/departments/tower-gr ... 999_BQ.prd
> 
> or would this be better?
> 
> http://www.halfords.com/technology/car- ... h-cable-1m


Hi, Will do the job, but multi-strand would be better as that is domestic earth cable, which has different purpose to auto "earth" cable.
Hoggy.


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## tttony

Neither cable is suitable. Just buy a reel of Halfords stranded brown 8amp cable.


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## TT-driver

Even a piece of 1,5mm2 220V/230V household cable will do just fine.


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## WallaceTech

Sooooooo.

I have performed this mod on my TT today. However before doing the mod i got the beeping on as soon as i switched the lights on. Now i have done everything apart from earth the cable to the car and the issue has gone away.

I was really hoping to put the lights on, hear the beep, and then earth the wire and hear the beep go away. I will still earth the cable to complete the job just a little frustrated that i could not prove 100% that its worked.

However the beep has gone away. I will check the brightness of the lights tonight when its dark


----------



## TT-driver

Since you have taken things apart and put them back together again, the factory earth wire's connection may have just improved enough to stay under the radar. After adding the additional wire, it should all be OK for years to come.

When checking the lights, turn on the normal lights, together with the hazard lights.

The blinking of the indicator lights should have almost no impact on the brightness of the other lamps in the unit.


----------



## starmagsi

Hi all,

New to the forum as my gf has recently bought a 2008 tfsi.

The rear lights have been playing up since purchase so today I have applied this mod, looks good so far - time will tell.

Thanks to the op for posting this, very informative post.


----------



## TT-driver

You're welcome


----------



## Danny732

Another one that has just completed this modification to right hand rear light (2007 Model). I had a new bulb holder fitted to the left hand side about a year ago that cost me about £100 to get sorted.
Following TT- driver's guide, plus the YouTube link, lights now working fine.
Thanks for posting the workaround guide.


----------



## MalcsTT

California3.2Quattro said:


> Spraying the connectors with Deoxit Gold is still holding up for me a month later. But the fix here is great should I need it down the road.


How did this fix hold up now that this is about a year down the line?


----------



## MalcsTT

Just finished doing this earth mod and the cheeser on my face is indescribable!! Legend. Not hearding that alert when turnin the key in the ignition was bliss 

Sent from my iPhone using Tapatalk


----------



## TT-driver

Another one who has beaten Audi 8) :lol:


----------



## MalcsTT

TT-driver said:


> Another one who has beaten Audi 8) :lol:


Now just to fix the other side thats leaking 

Sent from my iPhone using Tapatalk


----------



## TT-driver

I think it was "Peter-SS" who successfully glued the various colour parts of the lens together, making the unit water tight again.


----------



## brittan

TT-driver said:


> I think it was "Peter-SS" who successfully glued the various colour parts of the lens together, making the unit water tight again.


It was and there's a link in the KB: viewtopic.php?f=43&t=961665


----------



## MalcsTT

TT-driver said:


> I think it was "Peter-SS" who successfully glued the various colour parts of the lens together, making the unit water tight again.


Yeah i've watched that. Stuffs been ordered just waiting on it coming

Sent from my iPhone using Tapatalk


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## peter-ss

Just be careful not to allow the plastic weld to run anywhere it shouldn't.


----------



## Preet123

Hey guys, got this problem have very temporarily fixed it by cleaning out the connectors. I was just wondering which wire you would recommend to get the job done! 
Much appreciated!


----------



## TT-driver

Almost any mains wire that you could cut from an old TV or computer or what ever, is equal or better than the earth wire that Audi uses.


----------



## Preet123

Thanks dude, I'll give it a try this weekend!

Sent from my iPhone using Tapatalk


----------



## Bobo2211

Thank you for the detail guide, I just did this mod to mine, but I chose the earthing point right next to the battery, there is one or two bolts which hold the battery in place and I use that


----------



## TT-driver

Great to see how the additional earth wire makes it around the earth err world


----------



## Bobo2211

TT-driver said:


> Great to see how the additional earth wire makes it around the earth err world


btw, it seems that the problem occurs on the right rear light first, did you do the same mod to the left rear light?


----------



## TT-driver

Mine started on the right hand side too. I use the right indicator the most (left hand drive car and country).

But as these problems always seem to occur at the most inconvenient moments, I did improve the left side when I felt like doing it. Not because the TT was forcing me to...


----------



## 71309

TT-driver, thank you for this informative guide. From start to finish the job took an hour but my joy will last a lifetime.
Now then, do you have any advice on lower back pain?


----------



## TT-driver

:lol: 
From the money saved you can now get a nice massage :wink:
It's great to see how popular this 'mod' is.


----------



## Rene Pogel

Did mine this afternoon, both sides. I'd tried a week ago to just clean the contacts - miserable failure, if anything, made the problem worse.

Having had the light units out last week, that bit was easy. I chose a slightly different method to fix the issue - I cut through the earth wire to the 6 way plug right at the plug, stripped a bit of that nasty clothy harness cover back (so that about 4omm of brown earth cable was exposed). I then crimped and shrink sleeved spade connectors on, and tidied the harness covering up with black insulating tape & tie wraps.

I chose this method since the original earth cable itself is perfectly ok, and I didn't fancy crawling beneath the car to find a bumper bolt.

Finding where to install the bolt & eye on the light units was easy, thanks to the descriptions here and various youtubes. I checked anyway with a meter, it was the right trace (plus, you can see it going from one light to the next). I gave it a clean with some fine emery paper, and I slipped half a thin washer under the side of the round washer not pressing on the trace, to keep it all nice & level.

Reassembled it, tidied the tools away, maybe an hour total, and no more irritating light warnings!

What did strike me as odd (ie - a plain old Audi design screwup) was that the brown earth cable is a lot heavier than the other 5 cables to the plug (which makes perfect sense), but the contact is the same weedy little size for all connections. No wonder it burns. Hell, I've seen better electrical connectors on 1970's Italian motorbikes. Oh well, fixed now.

RP


----------



## TT-driver

I understand the re-using of the brown earth wire. Two reasons why I didn't do that:

1) I didn't want to interfere with the original wiring
2) On mine the original earth wire didn't provide the best earth possible: few tenths of Ohms resistance still.

Glad another TT is free from rear light warnings


----------



## Rene Pogel

TT,

Yes, I can understand you not wanting to mess with the stock harness - the gooey cloth stuff is a pain to cut through, and I almost had second thoughts before squeezing the wire cutters!

I didn't think to measure the resistance, just thought it'd be ok when I stripped the brown earth wire - reasonable gauge and clean copper. It certainly fixed the problem, thanks for all your posts & help.

Only one more thing puzzling me - the filler cap release. I tried pulling it, and then pulling it harder; nothing. The filler cap didn't pop open. It's an orange plastic 'string', so I don't know how hard it supposed to be pulled, or at what point it breaks. I pulled as straight towards the back of the car as I could, and tried a steady pull and a few jerks - nothing.

Can anyone who's successfully opened the filler cap this way give some idea of how hard it needs to be pulled? The normal solenoid release works fine, and I've lubricated the hinge & catch.

RP


----------



## TT-driver

You shouldn't be pulling very hard at all, I would _think_. After all it's just the solenoid action that needs doing. It may help if you push the lid down a bit. One of the youtubes I found claimed you'd need to pull very hard. Haven't tried myself yet.

Perhaps worth a separate topic.


----------



## poder

I went out and tried opening the filler cap manually a few times. Had to pull about 6-8 kg to release it, so yeah, quite hard!


----------



## userxyz

My 08 TTS passenger side rear light cluster has started playing up - intermittently flashing up errors, reporting an issue with with "right rear light" or the rear indicator. Bulbs are ok (as checked by a mechanic friend recently).

I haven't managed to remove the light cluster yet - does anyone know the size allen key required to undo the bolt holding it in?

Also, does anyone have the part numbers for both the connector, and the bulb holder assembly. I'd quite like to do an OEM fix if the prices aren't sky high for parts.

I've seen 1J0973733 referenced as the part number for the connector.

Thank you.


----------



## brittan

The screwdriver handle from the tool kit fits the fastener for the light unit.

The part numbers you need are at the end of this thread: viewtopic.php?f=43&t=332559

I'd strongly advise doing the extra earth wire mod by TT-driver. If you repair it as OEM then it's almost inevitable that the problem will reappear.

PS - TT-driver made a video: 



 :wink: :roll:


----------



## TT-driver

brittan said:


> PS - TT-driver made a video:
> 
> 
> 
> :wink: :roll:


Hmmm I'm afraid it wasn't me who made that video :wink:

I may have inspired the guy though


----------



## userxyz

userxyz said:


> My 08 TTS passenger side rear light cluster has started playing up - intermittently flashing up errors, reporting an issue with with "right rear light" or the rear indicator. Bulbs are ok (as checked by a mechanic friend recently).
> 
> I haven't managed to remove the light cluster yet - does anyone know the size allen key required to undo the bolt holding it in?
> 
> Also, does anyone have the part numbers for both the connector, and the bulb holder assembly. I'd quite like to do an OEM fix if the prices aren't sky high for parts.
> 
> I've seen 1J0973733 referenced as the part number for the connector.
> 
> Thank you.


Local indie did the non-OEM fix as part of a service. The guy I spoke to said he's seen it on many Audis and knew what I was talking about before I'd even finished my sentence describing the problem!


----------



## Rene Pogel

Just a thought; would it be a good idea to forward this thread to Audi? They might then do this on cars as they manufacture them, making this an OEM / non-OEM fix...

Does this problem exist on later and current models?

RP


----------



## ReTTro fit

Audi couldn't give a monkeys about it 
They'd much rather keep selling rear light clusters at some extortionate over priced rate

Sent from my iPhone using Tapatalk


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## TT-driver

I haven't had a chance yet to open up a later Audi to see what kind of materials are used. There is nothing wrong with the unit as is. All they should have done is some slightly wider connectors and a different material. Galvanised steel is not what electricians use to make connectors. I guess this time the finance department won the battle between quality and price.

Audi knows perfectly well what they are doing. Except this time they estimated wrong. Same story with the window regulator. They could have used better materials. But every euro/pound extra on the bill of materials adds 3 to 5 euros/pounds to the list price. Eventually you'd end up with a car that lasts 30 years without issues at the price of an air plane.


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## Bobo2211

hi guys, do you know what is the part number of a small rubber part that cover a hole right over the top of the rear light when it is fitted to the car?


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## Arsalan786

Userxyz - which garage did the fix for you? I've been trying to find someone in London to help me out with this without going to Audi but have had no luck so far...


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## Arsalan786

Userxyz - which garage did the fix for you? I've been trying to find someone in London to help me out with this without going to Audi but have had no luck so far...


----------



## texasgooner

I got this problem too this week. Nightmare, isn't it? I decided to spray the terminals with electrical circuit board cleaner as mentioned earlier. Seems to be holding up.

Another thought, to buy a tool to remove the terminals (from part 1J0 973 733 - 6 Pin Sealed Female JPT Connector) then re-crimp them, with gold ones. Has anyone seen these TE connectors online in gold? I only found these but do not look correct of course:

http://www.ebay.co.uk/itm/10-x-Econosea ... xyYANTYOXR

Also, I need a new black plastic part on right hand side where the two ball screws hold the light in (my car is LHD but its right side) I need to know that part number please. One of the two plastic holding ball is missing/broke.

Thanks!


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## tttony

It's really a waste of time and money to replace the factory pins and housings. The basic problem is that the earth pin/socket is only the same size and therefore the same current rating as the rest of the pins which only supply the individual bulbs. The earth pin/socket has to take the current demand for all the bulbs in the cluster and it is possible for all the lights to be on at the same time.

Adding the extra earth cable to each cluster is a permanent fix


----------



## texasgooner

tttony said:


> It's really a waste of time and money to replace the factory pins and housings. The basic problem is that the earth pin/socket is only the same size and therefore the same current rating as the rest of the pins which only supply the individual bulbs. The earth pin/socket has to take the current demand for all the bulbs in the cluster and it is possible for all the lights to be on at the same time.
> 
> Adding the extra earth cable to each cluster is a permanent fix


But I am replacing the factory ones with GOLD ones


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## brittan

The part number for the black plastic part is 8J0807454B
Check with pictures of it on Google and the part will have the number moulded into it.

If you do the extra earth mod, which I advise, there's no real need to address the burnt pin issue in the plug. If you do, you could just use a standard repair wire.
I did mine before any problem arose and found the pins in perfect condition.
I threaded the extra earth wire through the grommet and used an earth point in the boot (trunk  ) and also included a spade terminal join to enable easy removal of the light unit.


----------



## texasgooner

Thanks for the part number. Your fix looks real neat, perhaps I will be doing that (actually, last time I looked down near battery I saw I few brown earth wires too, I'll will investigate this at weekend).

I also noticed the manual fuel flap release cable was not coming through hole in boot where you unscrew the light bolt, but hanging down by battery, I guess this will need re-routing too, it's easy to get panel of there as I have also replaced/repaired the amp the other side. I assume its in wrong place!

Cheers


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## tttony

"But I am replacing the factory ones with GOLD ones"

Gold plated ones will be less prone to oxidation but will not have an increased current carrying capacity, but I think that your smiley means that you know that. LOL


----------



## texasgooner

tttony said:


> "But I am replacing the factory ones with GOLD ones"
> 
> Gold plated ones will be less prone to oxidation but will not have an increased current carrying capacity, but I think that your smiley means that you know that. LOL


Ah... I just thought, gold was better for connections?

Bronze?


----------



## texasgooner

@ Brittan, I have found the part online, when I looked at car at the weekend I could just see two screws (marked in green, that I think I can access), the other two screws I did not notice (marked in red). I am wondering if it's only possible to change when the bumper is off now? I hope not, I will look on Saturday, but those other two holes could fox me here?

Cheers


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## brittan

The part must be fitted before the bumper on the assembly line since the bumper clips into it.

However, looking at the orientation of those two holes in the red box, they could be accessible from under the wheel arch. 
Remove the wheel, remove some self tapping screws around the edge of the wheel arch liner and pull it back out of the way.


----------



## texasgooner

brittan said:


> The part must be fitted before the bumper on the assembly line since the bumper clips into it.
> 
> However, looking at the orientation of those two holes in the red box, they could be accessible from under the wheel arch.
> Remove the wheel, remove some self tapping screws around the edge of the wheel arch liner and pull it back out of the way.


Thanks, you are right I think. I always find it tricky to remove those screws lining the liner, will give it a go this weekend!


----------



## SwissJetPilot

My left tail light just gave out on me. I pulled the rear light assembly and used 320-grit emery cut into thin strips so I could get them in between the plug contacts and around each of the pin contacts. Gave both a good wipe with electrical contact cleaner and that seems to have been good enough to do the job.

Here's a DIY for rear tail light removal and gaining access to the bulbs.

https://www.carcarekiosk.com/video/2008 ... rake_light

And the bulbs you'll need...


Rear Turn Signal & Reverse (Back-Up) Light Bulb Size: P21W
Tail Light & Brake Light Bulb Size: W16W

Link to Osram light replacement selection chart -
http://www.osram-americas.com/en-us/app ... gmain.aspx


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## Hadaak

I noticed this issue lately. I installed a magnetic parking sensor a long time ago and tapped into the earth and live pins. The sensor started peeping randomly a few days ago and I thought the current draw was too much for the eath wire when I discoved the burnt pins. So I removed the sensor's earth connection from the earth wire going to the tail light and connected it to the chassis. But the problem came back and the light intensity faded again. I had already done a similar mod, connecting the blubs earth to the car chassis, on a mercedes 204 for both left and right lights. I thought of doing this to the TT too and just wanted to search if it was a common issue and indeed it is !!! I'm going to do both light. just wire the earth to the chassis once and for all.


----------



## Hadaak

did the right side. left side is ok but I wil l be doing it soon. pics coming tomorrow.


----------



## GaryG

Stolberg said:


> My question is: I have placed the additional earth connector to a bolt on the chassis/bumper (metal) adjacent to the light fitting, rather than down and underneath the car like shown in your photographs.
> Will this work? The lights are working. Is this a worthy earth point???


I'm not sure which bolt you're referring to either. You could test it, without your strap on it, with a battery and bulb.

(I did the fix a few days ago on an '08 model and used the normal nut under the car: I did consider a fused connection with the negative terminal of the battery.)


----------



## tttony

"I did consider a fused connection with the negative terminal of the battery."

There should never be a fuse in the negative return (earth) of any circuit on a car.


----------



## Hadaak

some pics of what I did:



















































__
Sensitive content, not recommended for those under 18
Show Content


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## Hadaak

This was just a quick fix. I ordered some anderson powerpoles and connectors to do a clean job later.


----------



## Hadaak

in case you need solid wiring:


----------



## GaryG

I forgot to mention that when I had to my rear light, I saw that the previous owner had obviously had the same trouble but he had spliced into the earth before the plug/socket and led a wire back to the/a nut on the inside of the wheel arch. This was a complete waste of time: as was shown by the typical burnt appearance of the earth terminal.

However, it did make me think: where does the standard earth wire end up? And is there any point cleaning it up?


----------



## Hadaak

No cleaning will help. It's the load on the connector which is generating too much heat. Going after the wire will not help too. 
Honestly just do like I did. Cut the earth wire from the rear light plug complety and wire the earth rail to the chassis. I did this for a W204 mercedes three years ago and it is still working; Make a solid connection and you're good for life


----------



## TT-driver

And so the lights are lit once more in the Paris, the City of Lights.

The earth wires are bolted to the boot floor, quite close to the respective rear light units. And while some resistance can build up between the wire and the earth of the car it is not enough to trigger the error message. The socket is the problem, almost always.

There is no need to remove the earth wire from the socket. Once the internals of the rear light unit have a proper earth connection again, the electrons take the path of least resistance: the new earth wire


----------



## Hadaak

TT-driver said:


> And so the lights are lit once more in the Paris, the City of Lights.


yeaaah :lol:


----------



## MarkyMark66

Hi, sorry to resurrect an old thread but I now the same issue on my Mk2 TT.

I have stripped out the boot liner, tool kit/spare wheel holder etc and have hopefully found what I deem to be a suitable earthing point to run this mod to, but I am struggling to work out how to post an image of this?

How to I attach an image to a post please?

Thanks in advance.


----------



## Hoggy

Hi MarkyMark, Use the "upload attachment" on each new reply.
Hoggy.


----------



## MarkyMark66

Thanks Hoggy, much appreciated! Think I've got it...... 

So is the point where the two brown wires run to a suitable earthing point for this mod please?


----------



## SwissJetPilot

There's two very good grounds in the trunk (boot). One on each side, conveniently located close to the tail lights. You can see the left rear in this picture. The right one is just aft of the battery, looks just like the left one. If you want it to look nice, pass the ground (earth) wire through the harness grommet. Peel back the tape, insert from the from outside, pushing in. Cut to length and connect the terminals.


----------



## MarkyMark66

Hi SwissJetPilot, thanks for the reply.

I have posted an image of what i deem to be the similar earth/ground in the boot of my Coupe, I believe your's is an image of a roadster and therefore slightly different?


----------



## TT-driver

That is is official earth point of the rear light unit. The thicker brown cable is for the Bose amp/digital sound processor.

It's perfectly fine to re-use these earth points for proper earthing of the rear light units. The aim is to bypass the crappy connector in the socket.


----------



## MarkyMark66

Cheers for the confirmation....


----------



## SwissJetPilot

Also, make sure you use a larger gauge wire to help take the current load. I went with either 2 or 2.5-mm (can't remember which exactly). You'll notice in my Roadster, it's yellow/green since I got my wire from a Renault dealer. German cars typically use brown for ground (earth).

And since you'll have both assemblies pulled apart to do this, it's worth replacing all the P21W & W16W lamps at one go so it's all done and finished and you can forget about the rear lights for another few years. Even if the bulbs look good, most of the TT's are old enough now that the bulbs are going to fail sooner than later anyway.

https://www.ttforum.co.uk/forum/viewtop ... &t=1609466


----------



## MarkyMark66

Yes, will be using 2.5mm earth cable. Luckily had a reel at work, it's not specific auto electrical cable but should do the job.

Thanks.


----------



## SwissJetPilot

Be aware household industrial wire is often solid, where automotive is made up of multiple strands. The difference is flexibility. Household wire doesn't bend as well, and is not designed to handle vibration or movement.


----------



## MarkyMark66

Yes it is multi-strand

https://uk.rs-online.com/web/p/switchge ... e/8034278/


----------



## SwissJetPilot

Great! Exactly what I used for mine. I'd also recommend you get a roll of the cloth electrical tape and spend the money (or borrow) a good set of crimping pliers. Makes all the difference to ensure you get a good solid connection that won't come lose later down the road. These are pretty cheap off Amazon, or a local hardware store. But they're better than messing with pliers and the tape is exactly what you'll find in the Audi.


----------



## MarkyMark66

Already have these so good to go, My Project for the weekend 

Thanks for all your assistance....


----------



## SwissJetPilot

Something I discovered when doing this earth-retrofit my Roadster; be aware of this little rubber do-hickey in the metal body work as you remove the light assemblies. It's on the upper corner of the metal panel between the trunk and where the light housing fits into the bodywork. There's just a small metal tab that this fits onto, and it's not secured very well.

Some people have already lost them and didn't realize they were ever there. There are two total; one left and one right. It sometimes comes off and gets caught between the red lens and the black plastic side piece. Or falls on the ground and you just don't notice it. Another genius Audi design. :roll:

EDIT -

"Stop Buffer Tail Light" or in German "Anschlagpuffer Schlussleuchte"

P/N: 8J0 810 967 - Left
P/N: 8J0 810 968 - Right

No rear light problem :)


----------



## brittan

The coupé has that little do-hickey too and they tend to fall out as you remove the light unit.

That's my MK2 RS coupé pictured.


----------



## SwissJetPilot

@ Brittan - Of course I snagged your post pics. Did you honestly think I was going out in this cold just to take pictures of mine?


----------



## Vanu

what is the part number of that rubbery thingy? I haven't noticed one in my coupe, part number eventually? And does it even matter if it's there or not?


----------



## MarkyMark66

I'd be interested in knowing the part number of the rubber part, as both sides were missing from mine.... :x


----------



## MarkyMark66

Have now completed this mod and lights now seem ok, but now have another fault on VCDS.

Before Mod....



Code:


 Saturday,13,January,2018,14:26:18:00001
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 17.8.0.1 (x64)
Data version: 20170721 DS276.2
http://www.Ross-Tech.com

VIN: TRUZZZ8J381033312   License Plate: AU51 FAB
Mileage: 176270km-109529mi   Repair Order:
Chassis Type: 8J (1K0)
Scan: 01 03 08 09 15 16 17 19 25 42 44 46 47 52 56 77

VIN: TRUZZZ8J381033312   Mileage: 176270km-109529miles

01-Engine -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: Malfunction 0010
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
47-Sound System -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: OK 0000
77-Telephone -- Status: OK 0000

Address 09: Cent. Elect.        Labels:. 8P0-907-279-30-H.lbl
   Part No SW: 8P0 907 279 K    HW: 8P0 907 279 K
   Component: Bordnetz-SG     H54 2501 
   Revision: 00H54000    Serial number: 00000007981489
   Coding: E1041E8280141C004F1800001800000000085E075C210802000000000000
   Shop #: WSC 01236 758 00200
   VCID: 458069880CA1E76EF9-8010

   Subsystem 1 - Part No: 8J2 955 119 A  Labels: 1KX-955-119.CLB
   Component: Wischer AU354   H08 0070 
   Coding: 00064784
   Shop #: WSC 01236

   Subsystem 2 - Part No: 4E0 910 557 B  Labels: 8K0-955-559.CLB
   Component: REGENLICHTSENSORH13 0100 
   Coding: 00149804
   Shop #: WSC 01236

8 Faults Found:
03098 - Rear Left Turn Signal Lamp (M6)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00111100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:09:00

             Freeze Frame:
                        OFF
                    Voltage: 12.20 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

00987 - Lamp for Brake Light; Left (M9)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:10:00

             Freeze Frame:
                        ON
                    Voltage: 14.20 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

00988 - Lamp for Brake Light; Right (M10)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:10:00

             Freeze Frame:
                        ON
                    Voltage: 14.15 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

00984 - Left Tail Light (M4)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:10:00

             Freeze Frame:
                        ON
                    Voltage: 14.30 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

00985 - Right Tail Light (M2)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:10:00

             Freeze Frame:
                        ON
                    Voltage: 14.30 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

01518 - Bulb for Back-Up Lights; Left (M16)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:10:00

             Freeze Frame:
                        ON
                    Voltage: 14.10 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

01519 - Bulb for Back-Up Lights; Right (M17)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:10:00

             Freeze Frame:
                        ON
                    Voltage: 14.10 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

03099 - Rear Right Turn Signal Lamps (M8)
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 179
                    Mileage: 176276 km
                    Time Indication: 0
                    Date: 2018.01.13
                    Time: 12:09:00

             Freeze Frame:
                        OFF
                    Voltage: 12.20 V
                        OFF
                        ON
                        OFF
                        OFF
                        OFF

After completing Mod, clearing fault codes.... Central electrics & steering wheel faults now ok, but now have passenger door fault?


Code:


Friday,19,January,2018,10:33:45:00001
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 17.8.0.1 (x64)
Data version: 20170721 DS276.2
http://www.Ross-Tech.com

VIN: TRUZZZ8J381033312   License Plate: AU51 FAB
Mileage: 176310km-109553mi   Repair Order: 2

Chassis Type: 8J (1K0)
Scan: 01 03 08 09 15 16 17 19 25 42 44 46 47 52 56 77

VIN: TRUZZZ8J381033312   Mileage: 176310km-109553miles

01-Engine -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
47-Sound System -- Status: OK 0000
52-Door Elect, Pass. -- Status: Malfunction 0010
56-Radio -- Status: OK 0000
77-Telephone -- Status: OK 0000

Address 52: Door Elect, Pass.        Labels:. 1K0-959-702-MAX3.clb
   Part No SW: 8J8 959 802 D    HW: 8J8 959 802 D
   Component: Tuer-SG         H02 0060 
   Coding: 0004660
   Shop #: WSC 01236 758 00200
   VCID: 3F8C7B606E7DBDBEB3-806A

1 Fault Found:
01553 - Motor for Central Locking; Passenger Door (V57); Lock
            012 - Electrical Fault in Circuit

Fault code not in the VCDS Wiki any one had this fault, and if so, how did you fix it?
Thanks.


----------



## brittan

The code description doesn't give much clue but a common(ish) place for a problem is where the wires pass through the rubber conduit between door and A-pillar. The wires can break there.

I did look for the part number for the little rubber things but I couldn't see them separately listed.


----------



## MarkyMark66

Thanks Brittan I'll check that.

Will have to contact Audi re the rubber thingy...


----------



## brittan

Looks like I answered that question 3 years ago:


brittan said:


> There's an item called "Stop Buffer" which sounds like the right thing but it's not shown in the exploded view so I can only be 99% sure.
> 
> 8J0810967 Left
> 8J0810968 Right


A quick check on the Left number gave:
https://www.ecstuning.com/b-genuine-vol ... 8j0810967/
so the numbers are likely correct.


----------



## MarkyMark66

Aha! Cheers, I found that thread earlier and asked for confirmation that these were the correct part numbers? Looks like they indeed are 

I've contacted my local Audi dealer for prices, lets see what super inflated price they come back with.....


----------



## SwissJetPilot

"Stop Buffer Tail Light" or in German "Anschlagpuffer Schlussleuchte"

8J0 810 967 Left
8J0 810 968 Right

These two are in the parts section with the other body bungs. Oddly, they don't have a position number, just a "-" at the end of the list and no reference on the illustration.
https://audi.7zap.com/en/rdw/audi+tt+tt ... 03-803036/

Prices range from $0.89 - $5.45 (US)
VAG 8J0810967 stop buffer Audi genuine OEM part
https://www.online-teile.com/volkswagen ... anguage=en

.


----------



## MarkyMark66

Thanks, these were the correct part numbers.

Have just heard back from local Audi dealer.....

The part numbers and prices are:

Left - 8J0810967 - £1.07
Right - 8J0810968 - £1.07

So have orders 2 of each, at that price it won't hurt to have spares


----------



## brittan

[smiley=thumbsup.gif]


----------



## TT-driver

Soooooo almost exactly 6 years after my repair of the rear light unit the bulb warning re-appeared!

Background for those who aren't aware: mine was built in the summer of 2006 and therefore is one of the oldest TT's around of the MK2 model. Because of its age I was one of the first suffering from the bad earth connector on the MK2. Improving the situation without paying Audi and implementing a solution that didn't affect the existing wiring led to this very topic with its solution.

And now the bulb warning is back, on the indicator. Yesterday I got all my measurement equipment out and I started measuring.

The additional earth wire still had 0.0 Ohm resistance to earth and the minus of the battery. And since I sprayed some anti corrosion wax on the connectors, 6 years later they are all still shiny. So my improvement still holds!

Then I opened up the rear light unit. Here I found that the glass wedge bulbs (W16W) were showing signs of oxidation on the small wires that connect them to the bulb holder. I replaced the bulbs, that were still the original bulbs, so close to 12 years old. And the problem is gone! 

Additionally I found the reversing light was actually in a worse state than the indicator lights. Could a faulty reverse light lead to an indicator light warning?

One warning on these W16W bulbs: do buy genuine bulbs from a real brand. Copy parts or cheap replacement parts don't have the correct shape at the glass wedge. These bulbs won't properly fit in the bulb holder. They'll loose contact and trigger the warning again. Genuine Philips, Osram or Toshiba bulbs only! You'll need 3 bulbs per side.

I had replaced the rear lights/brake lights already when fixing the earth connection. So I'm not sure when they will start triggering errors based on age.


----------



## SwissJetPilot

There's another possibility for intermittent bulb issues which I'm not sure has been discussed. For the three smaller W16W bulbs in the rear light assembly, there are three clear plastic rings that provide additional retention to secure the bulbs in place since it doesn't have a metal bayonet connector. I know at least one of mine is missing, and in retrospect, it could be a potential cause of bulb failures, or at least a potential fault or source of DIS error display.

Unfortunately this is not going to be a part Audi or eBay will have laying around. So hopefully an o-ring of compatible diameter should solve the problem.

For anyone who's replacing these bulbs, make a note if these retainer rings are present or not. Here's a link to a post with a reference to all the Mk2 head and tail light bulbs and part numbers.

https://www.ttforum.co.uk/forum/viewtop ... &t=1609466


----------



## TT-driver

Those rings aren't present on the early models.


----------



## SwissJetPilot

@ TT-driver - Ah, okay. Interesting. Mine's a late model '07 so I wonder which years have them and which don't. Maybe mine was a cut-over month and they only installed them on every other bulb! LOL! :lol:


----------



## TT-driver

:lol:


----------



## mcgon

Hi everyone. Firstly, apologies to bring up this old chestnut again - but I have a couple of specific questions that someone else's experience may be key.

*The issue*
Recently my right rear (2007 UK car) light cluster would pop up on the dash with either a 'rear right lamp' error or a 'rear brake lamp' error. Either or. Random. Dash warning would disappear after some driving. Then come back later. Sometimes multiple times per drive, sometimes the next day.

When this dash error was up, the whole rear right light cluster would be off. No lamps or brake lights. 
However - the rear right indicator and reverse light still work? (this may be important to diagnose? Why do these two always work when the cluster stops working - they are on the same circuit right? I don't understand this)
When the dash warning vanishes - all bulbs worked as expected again.

*Inspection & 'fix'*
On inspection of the right rear cluster, the connector showed bad corrosion and melting around the earth pin. I bypassed the earth connector pin by using a new earth wire bolted within the light cluster itself (from the metal earth loop as per instructions) and drilled a hole in the plastic bulb holder to feed the wire out the back of the bulb holder and added a female connector. I then cut the original brown earth in the connector and added a male connector to splice both wires in a solid connection. 
Worked fine, for a while but issue is now back.

*Advice sought*
1) Could the earth point at the end of the original brown wire be the issue? This was called out in the original post as an issue too. How do I find that earth point so I can clean it? The image link in the post is broken. I gather I need to take out all of the foam inserts and it is somewhere near the battery or under the light cluster? How will I recognize it? I plan to unscrew it, clean it, and reattach as the original poster did. I have a multi-meter - can I check it before and after? How? (sorry for the noob electrical questions).

2) Could it be a faulty or loose bulb that breaks the earth connection? All bulbs look good. Would a bad bulb connection result in this behavior - i.e. entire cluster goes dark. Nothing works except reverse and indicator. (again, I think this might be significant - why do they stay working - maybe they are just lower wattage? No idea.)

I think it must be 1 or 2. As the new earth wire is connected from the earth circuit in the cluster directly to the original brown earth wire with excellent connection.

Driving me nuts now. I'm disappointed with Audi but not here to moan. Lol. I had a mitzi fto for 13 years, never had so much as a bulb go in it. Obviously newer cars much more complex though.

Any advice very gratefully received. 
Thanks


----------



## tttony

If the new earth wire is taken to a suitable earth point of its own, it makes the original brown earth wire and any problems with it redundant. From what you say, it seems that you have just bypassed the problem connector. My advice would be to take the new earth wires from both clusters directly to suitable nearby points on the body. Some people drop the wires down to a bumper fixing bolt and others take them through the rubber grommet and use a bolt in the rear corners of the boot. Either way is good if there is low resistance to clean metal.


----------



## brittan

1) Since you have by-passed the original earth issue of burning at the connector pin, your new arrangement should be ok. However I agree with tttony that running a full extra earth line is the better solution. The internal earth points are in the rear corners of the boot, left and right. To expose them, remove the polystyrene tool holder things. If that is insufficient remove the vertical plastic panel at the rear face of the boot. With the boot floor etc removed, grasp its bottom edge and pull sharply upwards.

2) Yes the issue could be a duff bulb or poor contact where the bulb fits into the holder at the live and/or earth points. Check and clean them all. If the bulbs are 11 years old it may be a good idea to renew them, even if they appear to be functioning ok. Look for blackening on the inside of the bulb glass which is deposits from the filament and a sign of deterioration.

When a bulb fails, or apparently fails due to a poor earth, the system shuts down the supply to that bulb(s). If the earth can then support the current for the less used indicator and reverse lamps, that may explain why they still work. Possibly . . .

It is complicated by the fact that the lamps are pulse width modulated (PWM) where the supply is in distinct very short bursts. By varying the frequency of those bursts the voltage fed to the bulb can be varied and thus, its brightness. That is how the single filament rear bulb can be both tail lamps and brake lamp.

PS - If the right rear cluster had some earth pin burning, the left one may also have that problem. Check that one too.


----------



## mcgon

Thanks for your replies! Much appreciated.

Brittan, I did indeed remove the rear left (good) cluster also to inspect it. It was like brand new. zero corrosion on the earth pin. However, I bypassed the connector for the earth pin anyway. connected direct from cluster to brown wire as per the right rear fix.

My next steps will be to remove the boot inserts and check the internal earth points for any corrosion or poor contact.
also, remove the failing right cluster again and this time remove and inspect each bulb and reseat or replace them. They all looked in good condition when I gave them a cursory glance, but will remove and reseat / replace this time.

Your explanation about the reverse and indicator bulbs working makes sense. I think they are smaller lower watt bulbs too. Hard to know. The PWM setup is also complicating so who knows what is going on. 

Thanks again for taking the time to reply. Very much appreciated. I'll let you know how I get on after the weekend.

Cheers


----------



## tdi_van

can you upload again the pictures? they are not visible anymore


----------



## SwissJetPilot

Follow these directions for the earth (ground) lug connection to the rear light housing -

https://www.ttforum.co.uk/forum/viewtop ... 9&t=162142

You can watch this YouTube DIY, but don't use the exterior ground points he uses, they will only corrode later and fail. There's two perfectly good ground lugs inside the trunk, conveniently located close to both the left and rear lights. You'll have to remove the two black Styrofoam tool kit pieces to get to them. Be sure to remove the right one (battery side) first as they are interlocked. Then remove the rear, left and right trunk panels so you have easy access to the backside of the rear light wire harness.

Skip ahead to time stamp 3:40





Any good automotive electrical shop or car stereo shop should be able to sell you a couple of meters of 2.5-diameter ground wire. Brown is the typical German color for ground (earth).

1.) Disassemble the rear light assembly and drill a hole through the grey plastic housing, close to the ground trace. 
2.) Insert a SST pan-head bolt through the hole, ensure a good contact with the screw head to the ground trace. 
3.) Cut a piece of 2.5-mm diameter ground wire aprox. 6"- long. 
4.) Connect a ring terminal to one end of the ground wire and a male bullet (or spade) connector to the other. 
5.) Place the ring terminal onto the screw (between the two washers) and secure with a nylock nut.

Re-assemble the tail light assembly, it's now finished. Repeat this process for the other one.

6.) Cut a 1-meter piece of ground wire and route it through the tail light grommet (easier from outside to inside). 
7.) Route to the closest existing chassis ground-lug and cut to proper length (e.g. there's one near the battery and one just aft of the Bose amp location).
8.) Attach a ring connector to the one end and a female bullet (or spade) to the other end. 
9.) Connect the ring connector to the chassis ground lug.
10.) Connect the two bullet connectors and re-install the tail light assembly.

Repeat for the other side and you're done.

Hardware: 
* 2-3 meters of 2.5-mm diameter ground wire (wire strand, not solid)
* Ring connector (x4)
* Male bullet or spade connectors (x2) 
* Female bullet or spade connectors (x2)
* SST pan-head bolt (x2), washers (x4) and nylock nut (x2)

If done correctly, this method provides improved grounding for each of the rear light assemblies and circumvents the OEM ground wire. Therefore it is not necessary to replace the OEM rear light plug unless the damage is so severe that the other pins have been affected.
.


----------



## tdi_van

thanks for the link :wink:


----------



## mcgon

Here is an update

I removed the boot floor - right foam insert first - without much issue. I thought I identified the earth point. This is the right side one - note the two brown wires running into it. 









This is the left side one - one brown wire on this side. 









I removed and cleaned both earth point and earth wire connections.

















*THEN *- I realized, that the lights worked with these wires disconnected!!!!   i.e. They are obviously *not* the earth grounding points for the light clusters at all? :?: :?: :?: [smiley=bigcry.gif]

I was then going to remove the plastic trim and the carpeted side trim in an effort to find the real grounding points; but couldn't figure it out and didn't want to break any plastic clips on the plastic trim by just yanking it aggressively :roll: . So I put it all back together. I took out the light cluster and put two brand new 21watt bulbs into the brake lamps. The originals looked ok visually (see close up of old bulb below), but who knows if the connection or resistance was not good on either. I am hoping its a dodgy 21w bulb on the top row, hence the lower row (indicator lights and reverse lights) still works when my dash warning comes up. If it was earth, surely everything in the cluster should fail, not just the top row. Maybe... We will see. So no guaranteed resolution yet. I'll see if it happens with the new bulbs in tomorrow on my commute to work. [smiley=bigcry.gif]

PS. One other thing - Inside the little flap where you remove the bolt to release the light cluster - there was a red thing? on a red plastic wire. Like a cap? I have no idea what that was. I pulled it out and then just stuffed it back in. some sort of plug maybe? Hopefully nothing critical. You would need to remove the carpet side trim to see and I couldn't do that. argh.










Original bulb I replaced - looked ok - but might be very old.









P.P.S
One more thing... (Geez I bet nobody has removed the rear lights from an Audi TT as many times as I have this week.)

When the warning beeped on my dash only the two 21watt brake lamps failed. The indicator and reverse always still worked. When I saw the corroded earth pin I assumed this was the reason (confirmation bias at its finest - see below). I made a bypass earth wire to avoid the earth pin. It always intrigued me why only the top two bulbs would fail with a bad earth? So today I disconnected the bypass earth wire just to see if indicator and reverse still worked. They didn't. No earth. No lights - all 5 won't work. So now I think my issue must be bulb related as it was only ever the top two bulbs that failed. I think an intermittent earth would cause total failure of all 5 bulbs. We will see. I have replaced the two brake bulbs as mentioned with new ones so we will see over the coming days.

This guys also found that when one bulb is bad/failed/bad contact - both bulbs get shut off. https://www.ttforum.co.uk/forum/viewtopic.php?t=91834


----------



## jaybeeteetee

*there was a red thing? on a red plastic wire....*

Sounds like the manual filler cap release


----------



## mcgon

jaybeeteetee said:


> *there was a red thing? on a red plastic wire....*
> 
> Sounds like the manual filler cap release


Yep. That's what it is. The red cap pushes onto the bolt that holds the light cluster in place.


----------



## mcgon

I've had no more dash warnings since I changed both 21w bulbs. 

When the dash warnings happened intermittently and I saw my corroded connector pin, I assumed it was the earth issue.
Then I realized that only the brake lights were failing, not the indicators or reverse. so not an earth issue.
A dodgy bulb will cause both brake lights to fail. They looked fine visually. I could have probably just rubbed the lower bulb contact with light sand paper and reseated. but just as easy to put two new ones in.

Glad I did the earth bypass fix on both sides anyway. by the look of my connector it was only a matter of time.
Thanks all for the advice on this. The wealth of info on here was a great help!


----------



## brittan

Good, glad it's all fixed now.


----------



## mrdanward

Just bought all the bits to do this. The guides and youtube video are great. I've been meaning to do this for ages, but now I'm driving a lot more in the dark I need to get it done!


----------



## mrdanward

Did this today and it appears to have worked! No more failing lights and annoying warnings on the dash.


----------



## TT-driver

Glad you managed to apply the fix.

One more happy customer


----------



## tomasfuk

While browsing on another TT forum (German) I realized that there is one weak point more there.
The (-) bus is made of two pieces - one goes from the connector to the brake+rear lights (P21W bulbs) and the other one goes to the turn indicators + reverse light (W16W bulbs). In this picture red and yellow paths:










These two pieces are connected to each other, but the contact is not well done and may fail. When this happens, one group of bulbs causes errors while the other works fine. Which one - it depends on where the additional "chassis" wire is connected. Thus I decided to make a bridge between those "chassis buses".










Stranded wire 1,5 mm2 soldered - I chose places far away from plastic chips to avoid melting - and fixed with silicone glue (soldered stranded wires tend to break upon vibrations).

And finally, I chose another point for attaching the additional "chassis" cable, sprayed with preservative oil:


















At the end I measured the resistivity a) between both (-) bus segments, b) between the outside connector and (-) bus.
Both are approx. 3,5 mΩ


----------



## tomasfuk

Today I installed both chassis cables.
Voltage drop before: (between chassis and the (-) bus in the lamp)
left: 0,085 V @ 3A - still acceptable, the connector pin looks fine
right: 0,55 V @ 3A - unacceptable, the connector pin looks bad but no errors yet.
After the additional (-) cables installation: 0,015 / 0,020 V @ 3A [smiley=cheers.gif]


----------



## efunc

I need to do this tomorrow as my entire right lamp has now gone. I'll have to go out and source all the connectors and things. What size bolt worked best? Is that an M4 bolt? Also, do you need M6 ring connectors for the earth bolts in the boot of the car? And rookie question - does the battery need to be disconnected during the procedure?


----------



## tomasfuk

efunc said:


> What size bolt worked best? Is that an M4 bolt?


In my setup it's M3 (as the hole in the metal strip is ø 3 mm). Others who place the screw beside the strip use M4 or M5, both will work fine.



efunc said:


> Also, do you need M6 ring connectors for the earth bolts in the boot of the car?


Yes, these screws are M6.



efunc said:


> And rookie question - does the battery need to be disconnected during the procedure?


No need for that - only the right one is a little bit hidden behind the battery. I needed to take only the foam out.


----------



## efunc

Thanks tomas, good to know. I'll get on this in the next couple of days [smiley=thumbsup.gif]


----------



## efunc

well, after spending the whole day on this frustratingly I'm no closer to a solution. Like others I'd been getting the periodic bulb errors on the DIS and messages regarding the 'rear turn light right' for some time. periodically it would result in the rear right indicator not working, or perhaps the rear light or brake light too, but mostly I think they generally worked despite the DIS warning. Then finally the whole rear right lamp went last week and none of the bulbs seemed to do anything. Believing I could resolve this by adding the extra ground wire I set to work today. However having finished the repair all I've achieved is that my rear indicator now works ok, but not the brake light or anything else. The bulbs themselves look to be intact so I don't think that's the issue, but I've ordered a couple of P21Ws anyway. Interestingly, when I initially finished the repair and fired up the engine to test the light I don't think any of the rear lights were working on either side, including the brake light on the tailgate. I'm not 100% certain about that, but they're working now at least. So the problem currently is just the lights on the right rear lamp, apart from the indicators. Is it possible that the bulb holder is damaged beyond repair perhaps? The ground pin was slightly blackened, but not as severe as other's I've seen posted, and no real molten plastic. Could there be a fuse that's burnt out instead? Unfortunately my VCDS has just stopped working so I can't obtain a scan to diagnose what's happening.

The repair itself seems pretty good to me. I cleaned all the contacts and tightened all the bolts good and tight. I used 1.6mm mains ground multi strand and secured this to the ground bolt behind the battery on the right. Any other suggestions?


----------



## tomasfuk

I am a little bit confused.
Turn signal bulbs - they work.
Brake/tail bulbs - they don't work.
But what about the reverse light? Does it work or not?

I suspect that you solved only one half of the problem - have you read these posts?
https://www.ttforum.co.uk/forum/viewtop ... 7#p9089577
https://www.ttforum.co.uk/forum/viewtop ... 9#p9091149


----------



## efunc

tomasfuk said:


> I am a little bit confused.
> Turn signal bulbs - they work.
> Brake/tail bulbs - they don't work.
> But what about the reverse light? Does it work or not?
> 
> I suspect that you solved only one half of the problem - have you read these posts?
> https://www.ttforum.co.uk/forum/viewtop ... 7#p9089577
> https://www.ttforum.co.uk/forum/viewtop ... 9#p9091149


Tomasfuk, thanks for the pointers. I've re-read both those posts now, as well as your one again, and that might be the issue. I did look at the earth circuit inside the bulb holder when I had it out but didn't notice anything suspect, so I left it alone. I may have to give it a closer look and bridge the two tracks with a piece of wire. However, another possibility is that it is genuinely just one of the P21W bulbs, so I'll replace those first.

And just to confirm, yes, my indicator bulbs seem fine (no double tick sound produced by the indicator stalk like before) but the brake light and tail light are non-functioning. I can't tell if the reverse light works or not, I assume it probably does. I may try testing now by setting up my camera to record whilst I reverse into it!

***EDIT**

Yes, I can now confirm that my reverse light does work too having just filmed it in the dark. So all the bottom row bulbs work and none of the top row ones do. I will replace these with new Osrams first, and if that doesn't work bridge the lower and upper earth tracks.*


----------



## efunc

Success! Thank you all, I would never have figured out the earth pin business in a million years if it wasn't for the experts here. Adding the second wire to the chassis ground bolt obviously worked as prescribed but the reason I was still seeing the bulb error was that I genuinely had a defective bulb at the same time. The two things simultaneously were enough to confound me, but replacing the bulbs has now completely cleared up the issue and hopefully it'll remain good for a few years. [smiley=cheers.gif]


----------



## aeronaut90

This is now going to be a job for me over the Christmas holiday but I'm a bit puzzled at the moment. Both right hand tail and brake light showed the warning sign on the DIS the other day. No problem - must be a bulb failure as I did the earth mod a year ago. Replaced both P21 bulbs this afternoon and cleaned up the bulb contacts with a fibre glass brush as a precaution.

Still no joy. Linked a wire direct to the battery earth in confirmation but just the same so definitely not the earth fault. Reverse and indicator working fine. It's soon going to be dark so I've chucked the lamp cluster in the boot and put the car in the garage for the time being till I have more time.

Anyone else had rear light issues not related to the earthing issue?


----------



## mrdanward

aeronaut90 said:


> This is now going to be a job for me over the Christmas holiday but I'm a bit puzzled at the moment. Both right hand tail and brake light showed the warning sign on the DIS the other day. No problem - must be a bulb failure as I did the earth mod a year ago. Replaced both P21 bulbs this afternoon and cleaned up the bulb contacts with a fibre glass brush as a precaution.
> 
> Still no joy. Linked a wire direct to the battery earth in confirmation but just the same so definitely not the earth fault. Reverse and indicator working fine. It's soon going to be dark so I've chucked the lamp cluster in the boot and put the car in the garage for the time being till I have more time.
> 
> Anyone else had rear light issues not related to the earthing issue?


There was a guy very recently talking about the fact that the internal earth metal is in two parts and he had to install an additionally link between them. My wording might not be quite right, but that might be worth looking in to.


----------



## Solarblaze_uk

aeronaut90 said:


> This is now going to be a job for me over the Christmas holiday but I'm a bit puzzled at the moment. Both right hand tail and brake light showed the warning sign on the DIS the other day. No problem - must be a bulb failure as I did the earth mod a year ago. Replaced both P21 bulbs this afternoon and cleaned up the bulb contacts with a fibre glass brush as a precaution.
> 
> Still no joy. Linked a wire direct to the battery earth in confirmation but just the same so definitely not the earth fault. Reverse and indicator working fine. It's soon going to be dark so I've chucked the lamp cluster in the boot and put the car in the garage for the time being till I have more time.
> 
> Anyone else had rear light issues not related to the earthing issue?


The solution https://www.ttforum.co.uk/forum/viewtop ... &t=1868355


----------



## peteholloway

Just picked up a replacement pair of tail lights, part number 8J0945095K and 6 8J0945096K, replaced due to stress cracks.

I was wondering if these newer units (made in 2017) also have the bad earth issue and whether I should do the mod preemptively.

At the moment, only the left tail has the mod (and a burnt earth pin) and I'm waiting for a replacement connector to arrive.


----------



## tomasfuk

Being you, I should do the mod at both lamps, even with new connectors.
The question is not *if* it will fail but *when* it will fail. Simply a wrong design.


----------



## peteholloway

Thanks, was thinking along those lines too


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## TT-driver

In German, but these guys show exactly how an OEM repair is carried out and which tools are required.


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## SwissJetPilot

@ *TT-Driver* - Totally disappointed. All they did was replace the plug. They didn't address the root cause of over current at the ground pin. That car will be back in the shop for the same exact problem. :?


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## TT-driver

Well they did mention the workaround. But they thought the car was worth a repair with original parts. Normally I would agree. This time not so....Hence my suggested non OEM repair, which is now holding up 50% longer than the factory set up.


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## SwissJetPilot

To be fair, if I was the mechanic and someone rolled in with all that crap in their trunk, I wouldn't have done it either!


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## tomasfuk

TT-driver said:


> Well they did mention the workaround.


But not the our one. They mentioned a short supplemental wire soldered to the (-) wire just behind the connector (what I would not recommend).


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## Solarblaze_uk

Another headache last week with the rear lights presented itself. I've done the 'new' earth, and the two rail connection in the casing, then months later, a warning light appears AGAIN!. I'm thinking this has to be a bulb, turned out the bulb was fine after pulling it out and apply a 12v source to it away from the unit. The problem was the two side pins that connect with the indicator bulb, contact with the bulb wasn't enough force - I bent them inwards for a better contact with the bulb, all has been ok since.

I swear, if I get one more rear warning light error, I'm soldering each input wire directly to each bulb.


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## andys_tts

I'm about to do both sides on mine. Just a thought. If the pin is the issue, why can't you simply use the new earth point on the light cluster (drill and bolt) with the existing earth cable suppling the plug?


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## tomasfuk

You can, but two wires are always better than one.


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## Solarblaze_uk

I never actually made a new earth point, I just bypassed the earth pin with the original wire straight into the casing. It's been fine since


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## peteholloway

Mine was done like that on one light and never failed. Now I have two new tails with replaced connectors and two separate working earths.


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## fubar7

hello everyone,
after my rear drivers' side brake/side lights failed (burned out earth connector etc), i adapted the earth connection as described here and it worked fine. The passenger side was fine but i adapted that side as recommended but now the outside brake/side light on the passenger side refuses to light up. The dash indicates the bulb is out but when i replaced it, the problem remains. I have tested the connector and all pins are getting power and the bulb holder appears to be fine (is not burned out etc).
The bulb holder will not light a 21W bulb but will light a 10W bulb. Although the error message is now gone, this is still not ideal. The other side (which was the initial problem, is still working as it should).
Any advice to check the circuits etc please let me know. thanks


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## tttony

It's likely to be a poor internal earth within the light unit. See this thread:-









Another rear light failure mode.


I don't think that this has been covered here before. A couple of weeks ago my neighbour told me that my right tail and brake lights were not working. I had not had a bulb failure warning on the DIS. I carried out the additional earth wire modification years ago. I removed the light unit and...




www.ttforum.co.uk


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## Jezzie

fubar7 said:


> Any advice to check the circuits etc please let me know. thanks


There are two separate strips of earth metal inside the liight unit that are joined together by melting a plastic peg (the same way that all of the metal strips are held down). If you search the forum you should find pictures showing how to solder across this poor earth joint.


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## tttony

Jezzie, that is the subject of the thread that I linked to.

I would strongly suggest that soldering is not the best option.


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## Jezzie

tttony said:


> Jezzie, that is the subject of the thread that I linked to.
> I would strongly suggest that soldering is not the best option.


Oops!


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## fubar7

Jezzie, I get the idea you're suggesting. I will connect them without soldering (just to see)


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## SwissJetPilot

@ *Jezzie* - Generally speaking, you do NOT want to solder automotive connections; crimp connections are sufficient if they're done correctly. However in this case, there is a possibility that the ground plane inside the tail light assembly may have a bad connection (e.g. corrosion, poor metal-to-metal contact, etc), thus the soldered connection to resolve this issue.


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## E.L.Wisty

SwissJetPilot said:


> Generally speaking, you do NOT want to solder automotive connections;


SJP that's interesting - and useful advice, thanks - is that because of the level of vibrations in an automotive environment?


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## SwissJetPilot

@ *E.L.Wisty* - Generally speaking, yes. NASA has a few points on the topic -


Inspectors




201 CRIMPED TERMINATIONS GENERAL REQUIREMENTS


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## fubar7

Problem solved!

Although I have been told never to replace a car part unless it's broken (especially on an German car), I have heard others on this forum suggesting after the rear light fix, to just go ahead and retrofit the non-affected passenger side as well. I think that is wrong advice. In addition to that, it is suggested to replace all the bulbs as well, even when they are not an issue I believe is also excessive. The problem comes down to isolating the fault in stages.

However, when I upgraded the corresponding unaffected passenger side (which was okay at the time) it created a problem concerning one of the tail/brake bulbs on that side. It turns out it WAS the bulb at fault but because of all the changes there was no way to figure that out as being the problem. So best advice is don't replace was isn't broken, and work methodically. Although the fault was not due to a blown bulb, it would light a 5W bulb, so not being an electrician, I was at a loss to figure out why it was doing this. I believe the upgraded side grounding strip (which was on the outside brake part) reduced voltage to the corresponding side and that was the issue. If anyone can figure out what went wrong, please post it.

I don't think anyone should be sent to the Tower of London over it but tears have been shed...


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## FNChaos

fubar7 said:


> Problem solved!
> 
> snip--> However, when I upgraded the corresponding unaffected passenger side (which was okay at the time) it created a problem concerning one of the tail/brake bulbs on that side. It turns out it WAS the bulb at fault but because of all the changes there was no way to figure that out as being the problem.


Electrically speaking, an incandescent light bulb is a resistor.
Electrically speaking, a corroded / overheated / damaged connection is a resistor.

Your car checks for burnt out bulbs by comparing expected current flow through your lighting circuit with what is actually measured. A burnt-out bulb has infinite resistance and that change in resistance causes a change in current flow.

It is quite possible to have a bad / corroded connection that provides enough resistance to compensate for an open bulb. Fixing this connection would then exposure the underlining problem (defective bulb).



> I have heard others on this forum suggesting after the rear light fix, to just go ahead and retrofit the non-affected passenger side as well. I think that is wrong advice.


Proactively addressing known failure points is good practice. If you wait for things to fail they will likely do so at the most inopportune moments.


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## bigkevgarrickrfc

TT-driver said:


> Various topics appeared on this forum already regarding the rear light cluster packing up completely.
> As we've seen in the other topics, it's mostly due to a corroded earth connector in the plug/socket.
> 
> In my case however the connectors were still reasonably clean and no signs of overheating. Hopefully I now have a solution to the problem as it appeared in my September 2006 TT.
> 
> First of all, I noticed that the resistance from plug to the car battery was 0.6 Ohm and not 0.0 Ohm as should be the case. The root cause appeared to be at the other end of the wire, in the boot corner of the car. I disconnected it, used a fine grid sand paper to clean the bolt, the 'O' connector and the body work. Reinstalled the connector and result: 0.0 Ohm now. No resistance any more from plug 'all the way' to the battery.
> 
> Next point of attention: the actual connection from plug onto the bulb holder. Two issues here:
> 
> 1) the metal used as wire on the holder corrodes. This corrosion turns into electrical resistance. Current and resistance create heat. From there things just go pear shaped.
> 
> 2) the actual connector for earth imho is too small really. When brake lights, indicator lights and reverse light are on all at the same time, we're looking at 2*21 + 2*16 + 1*16 Watts = 90 Watts, close to 7A. That is a serious current.
> 
> I think this is a bit of a design flaw and replacing the bulb holder will only help if Audi uses a more suitable metal for the current ones. I don't know if they do.
> 
> This week I thought hard of a solution that did not involve running off to Audi and that had to be mostly reversible just in case it wouldn't work out. I think I've got it now.
> 
> First I looked for a suitable point for creating an additional earth connector, without the need of drilling a hole in the body. Found it:
> 
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> This is one of the 4 bolts holding the beam behind the rear bumper on to the bodywork. I connected a 50cm wire with a soldered O ring to it to this point. Applied some wax afterwards, protecting the bolt and connector from dirt and water.
> 
> Next I looked up a suitable place to drill a hole in the bulb holder plate:
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> I cleaned the 'wire' locally a bit (after taking the picture) and put a screw in with washers at both sides:
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> And the other side:
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> 
> Now the mounting on the car. Used a wing nut so I can undo the additional connector (and the whole light unit for that matter) without the need for any other tools than those supplied with the car. Here you see the light unit turned upside down, with the additional earthing connector connected.
> 
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> 
> The location of the connector was chosen in such a way that the likely hood of it getting into contact with water is quite small. Still after making the connection, I applied again a bit of wax.
> 
> So that's it: an additional earth connector to the light unit. It's installed on the right hand side now. When comparing the units left and right, I can see that the intensity of the rear lights and the reverse lights is more stable with the indicator switched on than on the left hand side. A clear sign that on the left, the unit is still suffering from a poor earth connection. Hope this solution will prove itself for years to come. Took about an hour to install and a couple of hours of thinking. If it doesn't work, it's all reversible except for the 3mm hole in the bulb holder. But that holder would have to be replaced anyhow in case this fix doesn't work long term.
> 
> _For the sake of completeness: this is the right hand side unit on a left hand drive car. When applying the same 'upgrade' to your own car, ensure that it's the correct 'wire' in the unit that you're connecting to earth. Otherwise you'll create a short circuit. And at all at own risk. Feedback is welcome.
> 
> Edit: restored the links of the pictures. Thanks to Brittan for copying them for the knowledge base
> Edit2: restored the links once more. Pictures are now hosted by the forum itself_


Hi I done everything in your post but the issue I'm having is when my side lights/dipped beam is on my rear indicators are 80% illuminated and when I indicate they brighten up to 100% all others work as normal.when I unlock the car the inner left bulb illuminates until car is locked it goes out.😵‍💫


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## SwissJetPilot

For whatever reason, my left tail light is still not functioning properly and is half the intensity of the right side. The lights are on, and there's no DIS warning or a DTC being reported. However it's very dim so I suspect of the ground plane or possibly the connector itself.

The left side indicator and brake lights work properly, so not quite sure what's going on. I've replace the two P21W bulbs on both the left and right lights so I know they're new. Guess I will be pulling the tail light assembly apart once the rain quits to see what's going on.

Depending on how things look, I may follow the recommendation from this earlier *thread* by *tomasfuk* post and solder the two internal ground planes together and see if that resolved the problem.

NOTE - this thread has been continued in this *post*


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## Wolvez

Both of my right brake light stop working last week. I assumed the ground terminal or the bulb failed but after inspection I found out both ground and bulb are OK. I sprayed conact cleaner and installed the bulb back but still not working. I swap the bulb with LED but still not working. I cleaned the terminal that makes contact with the bulb using brass wire brush and sand paper. It fixed the problem. I don't see any visible corrosion on the terminal.


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## Henrik964

OK did the ground project after a great guide. Right hand side, rear. All works, ground point to inner right side, Drilling point, hole for the screw and went through the OEM rubber stopper with the cable. All good. All works. No more beep and warning rear light out. Pics for documentation.


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