The rear wiper on my 09 A4 Avant has a mind or its own. Initially it simply started parking randomly. Then it began continuous running instead of intermittent and would eventually stop completely. Park was still random. Off and on would restart it. Yesterday it would start by itself and run continuously in dry conditions even though the stalk was in (both) off. Nothing seemed to stop it. Eventually it would stop, but only after 20 minutes or more of unnecessary running. Then it would start again. It seemed like indicating right to change lanes could trigger it. I was on a long drive at the time so didn't want to stop. Any ideas?
