Kev. I am 100% certain that this is what happens.
The vac hose set up is as follows. There is a vac pump on the back of the alternator. There are two vac hoses coming from this.
One vac hose goes towards three solenoids, each solenoid has a two electrical pins and two vac connection points. The hose splits into two, and connects to two of the solenoids and one is blanked. One solenoid sends a hose to the throttle body and the other two turn to one and go to the egr valve. All three solenoids have a two wire plug on top.
The second vac hose from the pump goes to the actuator which is mounted to the chassis and has a one wired plug.