I have a 1998 A6 with 130,000, and my cluster display has not worked in 3 years. Last weekend I went up to the mountains where the temp was around 17 degrees, and sure enough the display started working and was bright and crisp. Just thought it was funny!

 

Yeah, mine always works, but the temperature change affects what it does. Sometimes all the line are there.. other times, more appear. I would guess that as the temperature changes, electrical contacts are made and borken... Makes me think these things can be fixed.

 

I put a post with the same issue not too long ago, you may find it interesting, still in the fist page