Try closing off the vacuum lines to .. well at first, all the doors, and then try just connecting one door at a time. Alternatively, block off the vacuum lines closer to the pump so you can home in on the problem.
On your drivers door actuator, try monitoring the voltage / resistance on it as you turn the key in the lock (you shouldn't need to remove it). This'll give you an idea wether its working or not.
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black