Hey there,
My 05 A6 has had the left rear taillight, left rear reversing light, and left rear foglight fail for the 3rd or 4th time now in less than 3 years. this is only on the left side. It will work fine for about 30 seconds when u start the car, and then i see it short out. 1 out of the 5 lights in the left assembly works, thats it.

It was fixed under warranty once, then dealer said a year later that it needed to be replaced again for $385.00 dollars. I yanked it out and put it back in and it started working for a year somehow. Now it is out again. Does anyone know why this keeps happening i have heard 2 different things from 3 different dealers and its maddening since it is no longer under warranty! Please help I dont know how to get this fixed properly, the dealer is not helping!
Thanks

 

Symptoms sound like a bad ground, if all three bulbs are out. I would try using a continuity tester to determine if they are getting power and are grounding properly. Then trace connections and ensure clean, rust-free ground or connection. It's also possible a wire rubbed and shorted and you jiggled it free when you"yanked" out the assembly.

 

I just recently purchased a CPO 2008 A6 and the exact same thing is happening to me. I will be going to Audi on Saturday to have them try to find a remedy to this issue. I'm curious, did they actually replace the tail light assembly or did they just tell you they found the problem and solved the issue? I have a post up and I was told to clean the connections that go to the tail light assembly. I tried that but did not have the time to really experiment. Long story short, it "fixed" the problem for about 3 days and then the shorting started again.

 

If one of the lights works, it may not be the ground, if it all works when you first start the car, it's not the assembly, its possibly the lamp control module or the CAN bus to it. These things are little computers that can reboot themselves when disconnected and work for awhile. Get it checked. I don't have a diagram for your model but it likely does have a module, the 04 does.

 

This is a very common problem on the C6. The light unit itself goes bad. I had mine replaced a few months back. The issue is discussed on the C6 dedicated forums.

 

I took apart the bulb holder from the housing and found that there is a burn mark on one of the connection points where the black connecter plug attaches. I ordered a new bulb holder from genuineaudiparts.com and when it arrives Monday I will see if it works.

I have no effing clue why the damn thing is burnt. A friend told me that its pulling too much current and is causing it to short out prematurely. If this works for a year and fails again I wont be so pissed as the part is cheap but if it doesnt work, I'll be really effing pissed!

 

Quick update: just had the problem resolved this weekend by Bell Audi. The taillight bulb carrier was shorting and so they replaced it! I am so happy no to have to hear those freaking beeps anymore!

 

So the same fix they I had.