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.

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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