[UAHaerospace]

and, yes, the aggravation of 'non labeled' switches is, unfortunately, common with some builders... it's like a 'test' to see if you can figure it out!

the 'AUX' or 'EMERGENCY START' switch, a 'momentary' switch, is designed to link both sets of CHASSIS and HOUSE battery banks, so that you can either start the GENERATOR, or start the ENGINE, etc., if one of the banks are low. You can hold the switch in position for as long as you need to to keep the banks connected.
This switch is usually located on the dash.

the Use/Store switch, usually located near the entrance, is a UP or DOWN switch.... with UP being in the 'USE' position of having the HOUSE batteries powering our 12v fuse panel for all of your 12v lights, fans, water pump, furnace, etc., and also your INVERTER, generally.
The DOWN 'STORE' position DISCONNECTS the battery bank from the 12v fuse panel, for storage - when you don't want the HOUSE batteries to be used.
Most RVs, though, don't actually disconnect 'everything' when the switch is in STORE mode, since some safety devices, such as propane and co2 detectors always want to be powered. These will continue to draw down the batteries, albeit slowly.

Also, even if you are 'plugged in', and expect your Inverter's CHARGER, or Converter, to charge your HOUSE batteries, and even your CHASSIS batteries, if it has that capability, you must have the switch in the USE(up) position, as this allows the Charger to get it's charging power to the Batteries.

Generally, in most motorhomes, the HOUSE batteries power almost everything, even sometimes what you might expect the vehicle's CHASSIS batteries to power - such as the GENERATOR, the RADIO/VIDEO system, the Hydraulic Leveling JACKS, etc.

Only the the items that are solely vehicle related, or are tied to the ignition, will be powered by the Chassis battery bank, such as the engine starting, vehicle lights, but even including the automatic STEPS, as they are triggered by the ignition, and the door opening/closing, as a safety measure.


enjoy!