Advice: Until it breaks,,, DO NOT FIX IT.
When it breakes Progressive Dynamics 4600 may drop in repalce the WFCO electronics (the parts that go bad) allowing you to use the same power center breaker and fuse section.
or you can go whole-Progressive Dynamics... My coach builder did.. I have a Progressive Dynamics Breaker box, and a Fuse panel (Different box) and a Converter (Yet another box) in the strangest place they could put it (Not Progressive Dynamic's fault)
The fuse block has LED's to let me know what fuse I just blew.