Dave,
My neighbor has an older Winnie and he managed to get pretty good coach schematics right from them. Then all you have to do is get the service manual for the chassis and figure out how the two mesh. We did on his and it was not all that tough to do (I have worked as an electrician).
What I can't do is remember how any of his worked. I remember locating the "Engine Running" "signal" but I do not remember other than something powered a small contactor (relay) that was a pretty typical automotive cube.
Matt
