I’ve always taken it that we were lucky when we got our new ‘06 Ventura IV, given my pitiful knowledge of diesel coaches in 2006. It had a CAT instead of a Cummins that seemed to have issues at the time, was just prior to the conversion to diesel particulate exhaust systems, was right when sulfur content was minimized in fuel, and was right after the Beaver/Monaco move from Xantrex to Magnum inverters. Xantrex models were having problems, but the company eventually resurrected its reputation.
If the manual resource that Steve references doesn’t lead to an answer, the Xantrex company may be of assistance if you contact them with your symptoms. You could still have one of the original unresolved-issue models that they can help with. And as Steve says, ultimate help should be in Quartzite.
Joel