Hey guys,
very similar problem, changing out fan motor for Aqua hot under kitchen sink, no power down there . Old one was making noise and finally quit, then after a couple hours , I tried old one and new one directly to battery to be sure, old one started for a few seconds , new one fine , works . Checked fuses everywhere with multi meter , all good . Have not checked relays tho, which ones do I check ? , I see a bunch in the back closet, have not seen one in wet bay as you did , but will check again for sure. Fuse in wet bay above Aqua hot good. Thanks for any help.