92 300SD door lock issue
 

For some reason my driver door lock does not work property. When I unlock/lock the car from the pass door or the trunk, the driver door does not unlock/lock, but when I unlock/lock the car from the driver side, all doors unlock or lock. I don,t have an explanation, if I have a vac leak at the driver door, wouldn't the door will be have problems with locking and unlocking with the key at the driver side? I do not have the remote for keyless entry, I use the key at all time.:confused:

Chances are its a bad actuator in the drivers door. The switch in the lock will still run the pump for the other doors. The mechanical linkage will make the lock work from the key.

IIRC that system uses a combination vacuum / pressure line from the pump. That line might be broken going into the door.

Thank you for your respond. Okay then, I would start looking the hose starting at the easiest place for access witch is the back seat and follow the line that goes to the driver door. Does the leak will be active at all times or only when the key activates the door?

I would start at the door actuator itself. Pull the door panel and you can check there for vac/pressure. If you have nothing at the actuator I would check where the line enters the door.

vac/actuator pressure
 

I will have to get a vac/pressure tester in order to check for pressure at the line, or is any other ways to check the lines?

When you unlock at the driver door the vac actuator isn't needed because the key / mechanism does the work. When you unlock from another location the driver door then requires the vac actuator to do the work...which apparently it can't.

It could be the actuator that has failed or just the vacuum hose connection or both. I do know that my gas filler door actuator failed a while back, it became sluggish and refused to work. A replacement did the trick.

Steve A

GOT IT
 

Excelent information guys, know I have the nescessary information to know waht to look for it. I will keep report back of my findings. Thank you guys :)