In all of this discussion I am still not sure exactly which lock is the one in question.

The Prevost air lock or the dead bolt in the door?

If it is the air lock that is giving grief it will not be opened with a key as pointed out by Truk, but will require as has been suggested the air to be released.

If it is the dead bolt, that is likely to be actuated with a key fob and the coach door key will work. Does anybody have a key fob actuated air lock?

Before Bruce gets in the kennel with the dog and Pam is there an answer? If it was the air lock there would be the unmistakeable sound of the air cylinder being engaged instead of the metallic "clack" of the deadbolt.