Try a Ford Truck Dealer. The car/pickup dealers don't seem to have access to the MH/Van parts so much.
I was looking for wheel covers for mine. Only Ford store that had info on them was the Truck Dealer in Commerce City,,,, here in Colorado.
Jayco also had access.
Hoppe
2011 Dodge 1500 C'boy Caddy
2000 Jayco C 28' Ford chassis w V-10 E450
Doghouse 36' or so Trophy Classic TT