BEB,
All you are experiencing is related to voltage received from your chassis (starting) batteries.
From my experience, most electrical anomalies like this begin when the batteries are going south, lug connections are loose or corroded at the terminals, chassis grounding terminal is loose or corroded or connections at the large in-line fuses or at the Battery Control Center are loose or corroded.
This all attributes to electrical gremlins....so start at your source of power (ie chassis batteries) and work your way forward.
Over time, moisture and condensation can invade electrical connections, cause them short through corrosion and that's usually the case when you see slides opening on their own, generators starting on their own, awnings deploying on their own etc etc....or a group of dash components not functioning because they are all on the same large multi-pin molex connection.
A lot of these connections are found either behind the steering column along the dash or on the opposite side of the dash mounted to the firewall.
I have attached a photo of what happens inside these molex connections. This coach owner was experiencing all kinds of wierd electrical problems up until this was uncovered at the firewall.
Just some things to start with.