No surprise- that old Audi will be a money drain- glug, glug, glug-
You need to find the source of the battery drawing power. First verify a draw by using a test light in line between the battery ground terminal and it'wie. A short will pull energy from bwithe batteryre.attery, making the test lamp light up. You then pull out one fuse at a time, until you find the one whose removal ends the draw. Now you know which circuit has the problem.
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