We have a 2004 Tioga 26Q. Our auxiliary/house battery switch is on the control panel on the left as you enter. The 12 volt DC powered electronic controls on the fridge, water heater, furnace, etc., and interior lights normally are powered by the house battery and converter when hooked to camp power or when generator is running . The house battery disconnect switch operates a relay, you should hear a click or snap. If the relay is stuck/defective, it may not connect or disconnect the house battery. If the house battery is weak or dead, the switch/relay may not work. If you disconnect the starting battery, and fridge shuts off, fridge is connected to the starting battery. If you have a voltmeter, check house battery voltage on DC 20 volt scale. If charged, it should read 13+ volts, if nearly dead it should read 12 volts. Same with starting battery.
If you contact Fleetwood, they might be able to give you pertinent info.
