Yes, there is a battery disconnect switch, and if your floor plan has a couch in the front, it is most likely under the couch when the big drawer is pulled out.
If your tongue jack works only when the trailer is plugged into the tow vehicle, your trailer battery could be totally shot, or disconnected.
"Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace." James Madison
'08 34' Classic SO, '12 Ram 2500 4X4, 6.7L Cummins.