Originally Posted by tangofox007

It takes some amount of pressure differential to trip a check valve. Check valves do not necessarily guarantee a zero pressure differential. And it takes very little differential to move a lock actuator.

In any case, maybe the OP could disconnect his trunk actuator vacuum lines and report his findings. My money says that the mystery lock behavior ceases immediately.

Originally Posted by neumann

The central lock line is disconnected in the engine bay..is that not enough?

Originally Posted by neumann

On my 1980 300d I have disabled the vacuum lock system due to part failures and no desire to chase the gremlins. The lock related vacuum line is disconnected in the engine bay.

1. How do I make the driver door lock work in the fashion of not having to lock the door from the outside upon exiting the car. I want to be able to push down on the door lock knob and shut door and walk away with a door that is locked without having to use the key.

2. What is the deal with trunk locks. Sometimes I need my key to unlock the trunk and other times I do not. Sometimes within in 10 seconds of each other I can't make sense of it. What is the locking and unlocking sequences with the key? I am almost ready to hook up a remote trunk release