If you have an A8 or S8 that has a glove box that won't open, don't fret, it's an easy repair.
To fix it, move the passenger side seat as far back as it goes. Leave the door open and lay down with your legs hanging out of the passenger side door. Under the glove box there is a short cable it is around 4" long. It may be a little hard to find but feel around and you will find it. Pull on it until you here a click. Your glove box should be free.
They have a tendency to jam up. This is a pretty common problem on the A8.
