HELP! I've got an 1989 M3 Cecotto with a very annoying locking problem. Whenever I lock the car either manually or via the alarm nothings happens. All I get is a short buzzing noise from the drivers footwell. I've found whats making the noise (Crash Sensor) and replaced it (£94!!!) but this new sensor doe's exactly the same, just vibrates? Has anyone had this problem before.