Wiring issue

In laws just bought a 1995 coachman catalina 338fl the gfi in bathroom does not work and the wall out lets on that side does not work either and there is to lights in the slide for dinner and coach area that appear to be 120 volt also and they are not working either.breakers are all ok . Is there a place to get a wiring diagram on them so I can tell how it is wired? I am a car mechanic and would like to no how the voltage flows from the breakers to this breakers? Any tips our help is greatly appreciated