What I would do is check for vacuum and pressure at all lock positions. If the turnk and filler are working, I'd focus on the doors.

Compare the vacuum and pressure readings at each location. If they're the same, throw some new diaphragms at the bad actuators ($5 each). If they're not the same, then locate and test jucntions.

If one location is working then the pump is low on my list.

Hardly a revelation but that's how I'd do it.

Sixto
91 300SE
87 300SDL
83 300SD