Interesting quirk:

The door locks work perfectly when the doors are closed from either the inside or ouside (i.e. they all lock or unlock when one plunger is pressed down or the key is turned from any door) but when the driver side door is open, I cant get the plunger to depress and lock the doors. The passenger side door allows me to do this, so I'm not sure what the problem is....

From reading similar threads on here, maybe this is some sort of vacuum problem? if so, where, and how hard is it to fix? Thanks