No i dont think there is any sort of solenoid. To be honest mate I have no more ideas of what it could be, just going from the info on focusfanatics that says replacing that box fixes the problem.
But as you say, if you are not 100% then that is a lot of money down the drain! You could always buy it from ford and return it if it doesn't fix the problem? Make sure about their returns policy first though...