The E34 has a mechanical unlock that doesn't always work. On some models it only works on the front passenger door, on others it only works on the drivers door. It seems to work better if the battery has a little juice; not enough to operate the power door locks, but enough to activate the solenoid with some mechanical assist. I've found it to be unreliable. The E34 has been sitting for over 9 months until I figure it's worth the pain (back injury from an auto accident 5 years ago) to muck with it.The doors had mechanical opening with the key, as well as the normal electrical locking mechanism.