Note its position with engine off. Then start engine. If it doesn't move up, then there is a vacuum issue. If you use a vacuum tool to put vacuum on it, and it doesn't move, then it probably has a hole in it or the arm is seized.
If you disconnect the black hose to it, connect your pump to it and pump it, its suppose to stay put.
Another way to do it is to disconnect the hose, manually push the actuator in, put your finger on the hose nipple and let go of the actuator. It should stay. If it does not, then the actuator is bad.