The 12cuft Dometic located in a slid on the 2014 Bighorn I owned would not keep the refrigerator or the freezer cold / frozen even in the fairly mild heat of northern New England.
I installed an extra 12v fan that had a thermo switch that turned the fan off and on according to the temperature in the frig compartment. This helped, but would not handle the heat of AZ during the month of March. I can only imagine how warm the frig would get in any seriously warm weather.
I installed a refrigerator and freezer remote thermometer so I was conscious of any temperature variations. This Dometic unit seemed to work best when the ambient temperatures were between 50 and 60F. Temperatures warmer than that guaranteed warm milk.
Now warm milk is nice if you are a kitty. Not so much fun if your palate prefers cold milk with your cookies.
Seems to me that RV manufactures could pay more attention to the appliance installation instructions like OLD Biscuit mentions.
Oh well, back to the ice in a chest for chilling milk............
Lakeside
