Pulled 2017 fleetwood bounder out of storage and recharged and reconnected batteries. There was a fault showing on the command center with "OPEN GND" which I assume is that somewhere a ground wire is not connected. This is preventing any lighting even when running from shore power from coming on. I verified all by battery connections were as they were before storage (labeled lines, took picture prior to removal), but I am not sure where to begin looking. Any help/guidance would be appreciated.