I have a cranky, but lovable, 2001 BMW 330i; for several months the car has periodically drained the battery--dead. I've called AAA more times than I can count. The extremely patient techs at Foreign Autohaus tested and re-tested the electrical system and components, on two separate visits. The short version is that, after confirming there was no apparent reason for the dead battery, they concluded...it was a dead battery. They also confirmed the battery was still under warranty, so they installed a new one at no charge to me. Good show!