I assume when you say it does nothing that the generator does not start.
Check to see if the coach battery is charged. That is what is used to start the generator.
Yes cord has to be plugged into the generator output to power the coach.
As for any rebuild you will have to find a shop that can work on both the generator motor and the generator itself.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles