How does one troubleshoot the 83 240D Vacuum door lock system. Service CD has no info to the best of my knowledge.
My symptom is I dont think the system works the way its supposed to; however, I'm not even sure how it works. I discovered it when I was working on the Power Window regulator, the fact that theres a vacuum circuit on the door lock.

(1) Is the driver door lock supposed to unlock all four doors? This doesnt work in my car.
(2) Driver door lock cant be locked without using key. I dont think this is normal--problem might be in the driver side door?

What is the most likely thing wrong? Do you know where I can get diagrams? I have a vacuum squeezer.

The driver's door lock should unlock the other 3 doors, trunk, and fuel tank flap. From my experience, the driver's door will not lock (by hand) unless the door is completely closed. Your CD should have the diagram and a test procedure. I have the paperback manuals and the test procedure is under the central locking section. There is one vacuum element for each lock (except driver's door). Each vacuum element has two yellow plastic lines. The lines are color coded with a stripe, green is for the unlocking circuit and red is for the locking circuit (i think). Remove the carpets (front and back) and you should find the vac lines under black plastic covers. Find the locking/unlocking lines going to each door, and use your vacuum tester to determine which locking element is leaking.

Carrameow,

Since it isn't locking anything, I would first ensure that you are getting vacuum to the drivers door lock. You could use a vacuum source at this point to see that everything locks when the drivers door is locked. If you substitute your vacuum source for the input to that valve and all doors lock, you need to trace back toward the pump and see where you're losing vacuum.

Good luck,