In the BIRD/Trombetta setup, the Trombetta provides the two connections to both battery banks and the BIRD just provides the means to open or close those connections. In my 2014 Vegas and 2016 Axis, it was the way Thor hooked them up. For some reason, the house battery banks were wired to the on/off switch and not directly to the house batteries. Thor may have wired the BIM equipped Axis/Vegas differently. But it is easy to check. Just see if you are getting 13.5+v at the house batteries on both shore power and engine alternator.
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