Welcome to the Forum!
Sorry for the delay responding.
It is very unlikely you can get a complete parts list for ANY RV including new ones. Rv's are a compilation of components from many suppliers. You can get individual manuals / parts lists for your refrigerator manufacturer, furnace manufacturer, water heater manufacturer, etc. Lights, faucets and similar items are cheaper to replace than fix. Wiring diagrams depend on who (person) wired it. There is no exact method, like a car will have.
If you have specific questions about a component, please ask and we will try to help.