http://forums.tdiclub.com/showthread.php?t=229718

I wanted to get the attention of everyone struggling w the trunk latch problem. I searched every posting/commentary on the web, removed and disassembled mine, used white lithium on every part, reassembled and no change. I've been ignoring this for 2 years, this winter mine went from an annoyance (4-5 tries to lock) to a complete failure (over 100 tries to lock, sometimes just wouldn't lock, I stopped using the trunk).

I did 2 things. Bought a new one online but before installing tried the instructions at TDI Forum link above. I removed the cover panel on the lower trunk above the spare, its 2x10 mm bolts just above the floor of the spare. Then I unscrewed the 2x10 mm bolts holding the lower latch in place. Using my fingers and then a rubber mallet, I repositioned it so it was as high as possible, and perfectly centered. The old/existing latch now works perfectly, tested 20 times. PROBLEM SOLVED !!!!!

This may not work for everyone, a lot of posts from Audi mechanics say its an eletrical problem, just buy a new one. That may be true for some, but this incredibly simple fix worked for me. In fairness, today it warmed up in NJ so I may have to install the new one after all when it gets cold again, but hopefully I'm cured. If so, it means the problem is a very logical one: over time, the repeated force of closing the trunk pushes the lower latch further down. I have no idea how that correlates with cold temp, but mine was clearly lower and off center.

BTW, only PITA is getting the plastic cover back under the rubber lining of the trunk frame. Just have to work it all under by hand before snapping it back in place.

Any quesitons pls ask I'll be glad to answer if I can.