The '64 was a great year. First year for the turbo trans. The vacuum lines going into the doors are for the power door lock actuators. Your neutral safety switch is at the base of the steering column. It is an electrical switch but will also have vacuum lines that controls the park brake release. It's adjustable however might need replacing after all these years. These old Cads used vacuum to control a lot of systems, i.e. - A/C, cruise control, power locks, etc. These systems were not very reliable though, and as the car aged, vacuum lines became brittle and cracked and actuators leaked. Sometimes they were a pain to track down problems, especially the climate control.