JT- here's how you tell. Unplug the coach from shore power. Start the engine and wait a minute, take a volt meter & check the voltage on the chassis batteries (should be about 13.6V or a bit higher), then check the house batt's. If the house batt's are the same as the chassis, then the Vansco system is powering a solenoid to connect the pair while engine is running. If not, then either the Avalanche didn't include this feature, or the intertie solenoid has burned contacts & needs replacing.
If the volts are the same, all is good. If not, check LED#19 on the rear Vansco panel to see if it is lit after engine is running for a bit. If it doesn't light then the Avalanche program for Vansco is different and likely there is no interconnect solenoid. I'm betting its there.
Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project