I too have the same problem. And from my admittedly non-scientific experience, it occurs only when the temp drops below freezing (and happens nearly every night when it does go below freezing). The lights turn off when I pull up on the brake, so I'm going to tie a string from the brake to the seat top to see if that keeps the brake from depressing at night.

If anyone discovers a fix, please post. BTW, I have an 2006 A4 and this has been occurring during the last three winters. Absolutely no problems when temps are over freezing.

 

Last Saturday it happened again, this time the day temperature was already below freezing, but at night it dropped by 6 degrees and the lights came on! I hope someone can give some advise what is the issue and how to fix it.

Pavi

 

To hopefully your questions....

I had the "exact" same problem on my A4. Through this forum, which is a great source of info, I found that it was the "brake light switch" that had malfunctioned. Don't worry, it's an easy fix and cost around $30 and 15 minutes of your time.

I can provide you the details of the install, however, I have an A4. I'm not sure how A8 differs. I did a google search to find out how to replace the switch and it was easy.

I believe I found the how-to on this forum which actually got me to join this group.

 

I finally took my A4 for repair since the problem got worse and it was also time for annual maintenance. The guys could not find anything from the onboard computer, but due to the problem i explained, he said that Audis usually have the brake sensor/switch problem and he replaced it and...VOILA! no more problems with the brakelights and battery getting empty. Temperature outside was -17 degrees and the car survived!