Problem solved and fix implemented
Short story: It was the magnetic reed switch. New one solved the problem.
It is at most a $10 part but I could not find an exact match anywhere except from Airstream (through a dealer) the cost was ~$40 (all in shipping and handling).
I am very happy that this solved the problem. As I've heard the controller is more expensive and I never did find where it is located. The Airstream tech thought it might be under the passenger side jump seat in the back where the subwoofer is located.
Now I can refocus my efforts and work on getting my three new solar panels on the roof.
Thanks to everyone for their ideas and support!