[jcurtis934]

Why wfco has a fuse accessible by a user is a mystery to me. The inverter circuitry should protect the inverter from all the different faults one would encounter. You now have an inverter that is not allowing 120vac to pass thru with the inverter off or that fuse blown...which it should do. At this point, you have nothing to lose by making sure 120vac from the circuit breaker panel is going to the right input on the inverter, isolating the inverter out of the picture by connecting both romex cables together and noting the fridge runs. This assumes that you feel yourself to be safe working with 120vac power runs. Wfco should be okay with sending you a new inverter, but you can always tell them what is going on now before you isolate it from the 120vac wiring with no 12vdc power supplied to it. All inverters have a "decision tree" of : priority power present pass through to output circuit...if inverter on then go to idle mode, if inverter off no issue. If priority power not present and if inverter is on then pass inverter power to output section. If inverter is off...no issue.