Central locking
 

Hi guys I recently got a 1988 300ce and I'm having a hard time figuring out this problem with my locks.
Both the trunk, drivers and passenger doors unlock all the doors, however once I turn the key in the ignition to start all my doors lock by themselves. When I shut the ignition my locks again open.
Today I got out of the car with engine running and I locked my keys in the car. Luckily the sunroof was open
I have a six month old and I don't want this to happen with her in the car.
I appreciate any help.
Thanks

locks
 

I would think that the vacuum pump has been modified in such a way to make this work . Maybe the owner before you did a job on the vac/pump .The ignition switch is powering up the pump to lock the doors .I dont know any other way it could be done. Alive wire to the pump from ignition would do this .

Spartan I have been checking this out , and your car might have automatic locking as standard fitting . So it can be disabled .

Read your owners hand book . You should see a button with lock, or one with unlock, on it? Might be on the dash or on the door itself .

You might have an aftermarket security or remote keyless entry system with automatic locking feature. Does your car have a remote control fob? Are there extra wires at the central locking pump? Is there a locking solenoid in the driver door?

Sixto
83 300SD
98 E320 wagon