I think much of the issue is with a poor PDI. All these things were shown to us on our PDI, Fan was turned on to show it worked.. In fact I think it was on when we entered. Tanks, drains and locations were all shown and opened and closed. Electric, water sewer etc were all shown. I think his dealer let him down when they did the PDI, obviously they didn't cover these items. I had a list and didn't even bother using it as the service person was very through and organized. Even when I said I know how it works, he took the time to show us again, just to make sure.
sorry for your issues, we were lucky, picked ours up and lived in it for the next 5 months. Had no real warranty work needed, a few loose screws etc I just did myself.
2011 Toyota Tundra double cab