About the only thing A UPS UNIT may do is trip some GFCI circuits. I am assuming you are wanting power from the 120VAC outlets and not the 12VDC circuits.. Normally when parked you only have the 12VDC circuits working as the 120VAC is only powered up by plugging into the shore power pedestal or being run off the generator...
Check your GFCI wall receptacles that have the PUSH BUTTONs in the center and see if one of those has tripped. Usually several 120VAC receptacles down the string will go off when the GFCI one gets tripped.. You should have a GFCI receptacle whereever water is located like the kitchen sink area, the bathroom area, the wash up area sink in the bedroom hallway etc... I suspect yopu will three of these installed in your trailer.
This is what a GFCI 120V RECEPTACLE looks like
Also it is kinda neat to fill out your signature line or profile line to show what RV items you have. No one can help very good not knowing what RV UNIT you are talking about...
Roy Ken
