From memory (Which can be dangerous!), the majority of the fuses on our 04 40' Allure, are in the basement bay below the drivers seat. Though a second set of fuses are in the basement on the passenger side, with the fuel filters.
You don't mention what CC you have? I see 38' in your profile. Do you have two heating fans on the front zone? One by the steps, the other neat the galley area? Had the Squirrel Cage Fans on the heat radiators, been making more noise then normal? They're known to go out form time to time, and need replacement. Some just retro pancake fans, others swap out the full heat register with already included pancake fans. The pancake fans are quite a bit less loud
If you don't find a bad fuse, you might check into Roger Burkes Aqua/Hrdro Hot board. Roger does a good job of working thru the posts, provides solid advice, and has the latest and greatest parts available.
RV Hydronic Heater Forum
Best of luck to you,