A4 B7 totally screwy intermittent tail light problems

[Kwakazaki]

Apologies for the PM when we have never conversed via the forum previously,

Hugh from EuropaParts suggested you guys might have the knowledge I'm seeking.

I have had all kinds of weird things happen with the tail lights on my 2006 A4 B7; that I've owned from new.

Bulbs blow singly, in pairs and three's, on the left and the right, indicator, rear, brake and reverse lights, indicator might do double time, and often bulbs go out... and then come back on again some time later!!!!

To give you an example, Friday night on arriving home (I drive 40miles each way each day) I realized my rear right turn signal was out.
Note - I check my rear lights all the time and keep a screw driver in the trunk!

The bulb did not show any sign of blowing, anyway I removed and replaced with the bulb from the reversing light. On trying the indicator the turn signal now worked, but the rear light had gone out. Just so you understand, I realize that this makes no sense at all... frustrated/exasperated I went inside to search forums. 30mins later I decided to try again, and low and behold.... now all the lights worked! I did not change or fix anything, just put the bulbs back in the holders!

At this point I should also say that majority of the time I've been having problems with the left (drivers) tail light cluster, whereas this Fridays problem was on the right.... just to ensure you have the full picture of just how weird this is!



While I had little solid evidence, and just based on a few forum posts, I decided to add a new/independent common/ground on each side, as suggested.... sheet metal screw and new wire back into rear wing and mounted to the body.... tested against the battery negative and got 0.5ohm, so all good.

And actually, since I did this at the weekend.... nothing has gone out, no problems with intermittent tail light issues... but I'm not yet counting my chickens

Because Hugh made me realize there more weird stuff:

• The 'bulb out' warning light on the dash never shows
• VCDS shows no errors codes

I even tried pulling a headlight bulb and I still get no dash warning light.

So my reason for contacting you is that I found this post....
http://www.audiaddict.net/viewtopic.php?f=87&t=331

Which refers to modification of a light control module on a B5.

I might be clutching at straws, but could such a module be the cause of my ills?
And if so... do you have any idea what the equivalent module is on a B7 (2006)?
I have searched and searched and cannot find any reference to such a thing????
Only headlight range modules, and I'm sure its not that.

Apologies for the super long mail, but its been a long road to get to here

Here's hoping someone can help shine some light

Regards,

[mike@hidconcept]

Sorry to hear about such issue.
I would love to provide any help/support on AZ community.
However, this is not a common issue. Based on a symptom of problem you have; turn signal kept on going bad, I would suggest checking on turn flasher relay and also check on the hazard switch. If you have done any modification, you should go back and try the stock setup.
If it has all stock setting, I would take it to a dealer or audi mechanics so that they can diagnose the issue. When it comes to this kind of electrical issue, it's very hard to troubleshoot.
Good luck!