I have a forest river sunseeker class C, I run my gen set for test and it starts and runs fine. But when I turn on the ac nothing happens and the lights draw down on the battery. I checked the circ...
What year Sunseeker? Only in the past couple years have Forest River moved away from a special receptacle that your generator uses for power to an automatic transfer switch. I'd almost be certain the shore power needs to be plugged into the gen outlet.
If that isn't the case, check the breaker on the Onan generator itself. That might be tripped.