Go to the following link on the Owners section of the Thor Motorcoach website:
https://thormotorcoach.com/motorhome-owners-resources/
Click the Contact Customer Care button and fill out the request form that opens. Be sure to fill in the model, year, and VIN because as Thor makes mods during assembly they update the construction drawings for your particular RV.
After Thor receives your request, they will forward the requested drawings/schematics as attachments to an email. Generally they will reply within a few days.