I have a 1983 300SD TurboDiesel and when I opened my driver door this morning, it opened, but none of the other doors, the trunk, and the gas lid, unlocked how they are supposed to? I'd appreciate some suggestions on some things to check, or on what can be causing this malfunction. Thanks for your help.

Usually this is a problem with the vacuum system.

Did the car was standing still for a long period of time? Or, did you manipulate the locks a few times with the engine off?

Try running the engine for a while and operate the locks and see if they work properly. If they do, you could have a small leak at one of the vacuum hoses that lets the air bleed while the car is stopped. Also check if it is the driver's door contact. Just operate the central lock system from the passenger's door or the trunk.

How to fix it? Well, if it is a leak at one of the hoses, it is easily fix. The problem is finding the leak (very time consuming!). Usually, sections of the vacuum system are tested with a vacuum pressure monitor. If at one section the pressure drops fast, there is your leak. Make sure also that there are no loose vacuum hoses in the engine compartment!

A. Rosich
S320, 1998
E320T, 1995

tonybenz,
You may find some help reading the thread listed below.

http://www.peachparts.com/shopforum/diesel-discussion/17031-82-300td-c-problem.html

Good luck.

Rick

The 300SD would be a very different system than those described above. It DOES NOT use engine vacuum. It uses a bi-directional pump that sucks and blows. It uses a single air line to each element.

The pump is in the trunk with the spare tire. It is activated by only the drivers door (I think on an 83; later years worked from the pass door and trunk)

Actually I checked and there is one switch in the drivers door. It carries power from fuse 13 through either a blue wire for lock or a yellow wire for unlock. This should be monitored at the pump while someone works the lock at the door.