Not sure what you mean by 'power', there is often a 'black box' or 'brain' electric module involved as well.
I have a 2009 41DS, not a 2012 50, but at the end of the day the thruster is going to be a 3rd party item like from Lewmar or something.
Have you traced 12 volt power for the control circuits and the main power circuits and such up at the thruster unit itself before presuming it is a fuse issue?