Q. With the battery switch, located inside the door, in the store position will the house batteries charge when on shore power.
A. No - As far as I know, this is true for all trailers with the electronic USE/STORE switch.
Q. Shouldn't the shore power run the jack regardless of battery charge status.
A. I don't know. It depends on how the trailer is wired and that varied, over the years, models, and maybe the assembly crew. Logic tells me that since the trailer is disconnected from the batteries in STORE mode, that the converter is connected to the trailer all the time. But the jack on my previous trailer jack was wired to the batteries direct and would not work unless the batteries were charged or charging. The jack on my 2002 Classic is wired from the trailer fuse panel and doesn't work unless the KILL switch is on. Did you try putting the trailer in USE to see if the jack would work on shore power? I have read ere that sometimes the USE/STORE switch won't go into USE if the batteries are completely dead. Folks have had to charge p the batteries with an external charger to get the switch to work.
Q. What could be draining the battery while the trailer is stored?
A. Several things, again depending on various factors. Typically the subwoofer, if you have one, is always drawing power. An inverter always draws power unless it is turned OFF on its control panel. The propane detector is typically wired direct to the batteries and draws power always draws power. Maybe other stuff.
For storage longer than a few days, a battery disconnect switch right at the batteries or disconnecting the batteries works best.
“You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins