Trailer/5th wheel OEM manuals are VERY generic.....nothing of real value.
Brochures have more info.
You can put together your own manual.
Write down Brand/Model of appliances/components (fridge, Water heater, Furnace, A/C Unit, converter, water pump, etc. etc.)
Then do a Goggle search for 'service manuals' (using the specific brand/model number)....print them out and place in a 3 ring binder. You will then have a manual that is useful with real info.