I have the Xantrex Freedom SW3012 3000 watt pure sine wave inverter in mine, but I left in the fridge xantrex too, since it works perfectly for that application. You must have an issue with a battery, battery connection, or maybe the fridge itself. Check all of the battery connections first.
2014 Cedar Creek 36CKTS Explorer
Xantrex Freedom SW3012 inverter/charger
2009 Silverado 2500HD Duramax Crew Cab short box
Demco Glide Ride pin box
Demco Hijacker Autoslide 18K hitch