Dutchman Astoria, bad converter?

Probably the easiest way to tell is by measuring the DC voltage right at the house battery posts.

If the voltage is in the mid-13's or so, your converter is still supplying a "float" charge to it.

If it's down in the 12's, it's not getting any charge from the converter.

If it's not getting any charge, check to see that the converter is plugged into an AC outlet (assuming it's not permanently wired-in), and that it's turned on.

Also check to see that the 120VAC circuit breaker which powers the converter isn't tripped or turned off.

If it’s plugged in 24-7 then the charger may be boiling the battery. TT converter/chargers are cheap and not multistage units that go into float mode. His battery may be done!

The newer 3203BH have the power center under the fridge. The converter should be behind the brown or black panel under the fridge. You will have to remove the panel to gain access to the lower portion.

If the converter is not under the fuse panel, follow the larger cables connected to the right side DC fuse panel. The fuses, not the beakers on the left. Two will be connected to the converter and the other two connect to the battery.

Is he sure be doesn't have the battery disconnect turned off?

If he has inside lights when plugged into shore power the converter is working. If he has lights when plugged in but no lights when he's disconnected from shore power, either the battery is dead or the fuse between the battery and power center is blown.

Thanks a ton for the replies.

Family of 6, living in it while their new house is being built, wintertime...so help fixing this is much appreciated.
Hard to imagine a <1 year old converter being defective, but of course stranger things have happened.

We'll work on it, and hopefully have a resolution to share soon.