@ 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. :?

 

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

Inspectors

201 CRIMPED TERMINATIONS GENERAL REQUIREMENTS

 

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

 

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

Thanks for posting this.

 

cheers man, very informative and useful :wink:

 

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

 

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.

 

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

 

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!

 

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.

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.

 

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?

 

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...

 

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

Thankyou very much for the 'How to'

 

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.

 

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!!!

 

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.

 

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.

 

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.

 

Guys, what is the usual fault ?

 

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.

 

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!

 

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.......

 

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.

 

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!

 

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]