As you have found out there is not much to look at when you take apart this type of EXV. It is very unlikely that the push rod is hanging up. As for the power head you will need to leave that to your imagination. The actuator either works or it does not. It only takes at most 30 minute to trouble shoot, that's it. This is where ohms law applies.
Originally Posted by ed-man
An EXV has to be told what to do, If I were you I would not look at it for more than 30 minute in your last effort and final test. Its very clear that your problem lies elsewhere.
This is so basic that on average it should take no more than two hours for a true diagnosis. A decade box would help for sure.
Understand the symptoms and you will and you will find a solution.