Took mine apart and found that the house lock just had a small diameter circular spring that had broken. Like you, didn't have the key for the deadbolt when I bought the rig so took the entire lock assembly to a locksmith and had them cut me a key for the dead bolt.
They didn't have the spring, so I zip tied the house lock unlocked while I tried to find that spring. Used only the dead bolt for several months. Finally found the spring at an Ace Hardware.
My old Bounder, and my newer Winnie have the same lock assembly, this is a picture of the Winnie. This rig was also missing the dead bolt key when I bought it. And the house lock has a tendency to lock itself.
House Lock...Because of that tendency, I've just zip tied the lock and will only use the deadbolt from here on. Just my idea on how to work around the problems many of these locks have...