I can only echo what Roller4tan said.....
for wiring diagrams, the general diagram is all that is available..... and the trailers are often wired a little different than the diagram, and sometimes WRONG, but the general diagram kinda shows how it should be wired....
so your kind of on your own, which is why I always suggest that a DIY owner should purchase a "wire tracer" to carry in the trailer for when its needed to find how and where the wire runs thru the walls that you suspect is causing problems...
the owners packet should have a manual that gives the information of the components installed when it was built... but a previous owner may have changed it at some point, so it really needs to be seen to know for sure....