How do you check these parts - Update

[john108]

I have the heater Box totally Disassembles and trying to decide how to check some parts.

1- In the picture below, Is the part the "Time Delay Relay" ?  That is my guess based on the service manual schematic.
How do you verify that it functions?

2- The actuator marked with a "B" :  It has a vacuum port on both sides.  I don't know how it functions internally.  I got a hand vacuum pump to test it.  It doesn't take much vacuum to actuate the door.  With the door dis-engaged, I tested each side of the actuator up to 22 inches vacuum.  It lost 1 to 3 inches vacuum per minute.  Some of it could be my setup.  When I connect the linkage to the door,  The actuator still functions, because the spring (on the linkage) snaps the door one way or the other when you pass half way.  BUT: in one direction, the linkage doesn't let the actuator reach full travel and vacuum doesn't climb at all even though a few inches of vacuum is enough to flip the door.  After the door flipped, the vacuum settled at zero and wouldn't pump up.

I was hoping someone knows how it functions internally.  Is it a diaphragm (that may be cracked) or sliding parts that can leak.

If the option is to replace, Do you know where they can be obtained? There are 3 different actuators on the heater box.

[john108]