According the the documentation
I have (from 2012 but probably did not change), the park brake wire is the only wire that has to be field wired by Newmar. It's light Green/Red and is located on the top side of the dash panel. I believe this is grounded by the parking brake switch. Improper grounding can make electronics do strange things, for example, turning on the lights can make an alternative ground path for whatever is turning on the parking brake light.
If it is not this wire the issue is most likely a Ford issue.
The chassis section is should be under warranty (3 yr), and the coach section hopefully still as, being a 2011, if I were you I'd keep after the dealer until it's fixed.