Hi j.courtoreille,
Welcome to the Heartland Owners Forum. We have a great bunch of folks here with lots of information and all willing to share their knowledge.
We have a Tools tab at the top of the page and there are lots of
user guides there. Most made and submitted by folks that actually use the units,,, owners. You might check there, and maybe one of our other members will jump in with some help. If nothing soon, you might call Heartland Customer Service and ask for some help, don't think they will send a complete diagram.
You might give us a little more info on the problem your having also.
Jim M
I am moving the thread to a better area also.