You do definately need to have someone who is knowledgeable and has the right test equipment (good multimeter) and knows how to use it. That may be you, but probably not.
The risk to you is that if the controller is malfuctioning it could cause voltage problems that will damage the various electrical items in the coach. If that happens, it will be much more expensive than having the generator looked at/repaired by a knowledgeable person.
As a "do it myself" person, the most important thing is to know when I do NOT know how to do something. Know what you know, and know what you do not know.
