It could be the door switch itself or the connection there. The vac pump has to run long enough to 'switch over' (complete an open or close cycle and turn off) or it will sit there and play dead until its disconnected.

Try getting it working and run several cycles of lock/unlock using the key in the door and see what happens.

If these is a leak in the vacuum plumbing, the pump will not build up enough pressure to switch over to the other cycle. It will run until the relay timer shuts it off and then just sit there.