The "typical" Damon Class A has a house battery disconnect. The switch for the system will be inside the coach and can be labeled with stay-store, connect-disconnect, etc.
This system only disconnects the house batteries using a solenoid that is part of the Battery Control Center (BCC). To operate, there must be a good charge in the house batteries or the solenoid can fail to connect/disconnect properly.
The BCC should be a device that looks like 2 solenoids end to end with a group of fuses next to the solenoids.
The BCC primarily does 2 other actions...
Operates the Start Assist to "jump start" the engine with the house batteries and
Feeds engine alternator power to charge the house batteries.
See a photo of the BCC from a Challenger at the bottom of the thread here:
2001 Challenger: volt..batteries..replacing..any power in the coach
First, the batteries must be in good order, then you can find and check the BCC with House Battery Disconnect.
Hope that helps.