@Mr Sunshine -
Unfortunately I don't have a BIRD/Trombetta - in about 2018 they changed to the BIM160. Ed's guide is invaluable, though!
I thought I checked it, but it may have been the battery leads that I checked, which were wired correctly. House side went to house, chassis side to chassis battery. Thanks for giving me something to try.
BTW - when not using your RVs long-term and not on shore power like on a RV storage lot, do y'all completely disconnect the batteries? I would think so. Sorry if it's a dumb question.