Our fridge would always do that when the drain hose got plugged. You might see if yours is ok. If it has a hose ending in a cup behind the fridge, there is a plug in the hose end with a tiny hole that needed cleaning every year on ours. Pl;ug is removed easily for cleaning. Do NOT just leave plug out, that makes things worst per a poster here.
2010 Ford Expedition TV
2010 Outback 230RS Toybox, 5390# UVW, 6800# Loaded Not yet camped in Hawaii, 2 Canada Provinces, & 2 Territories I can't be lost because I don't care where this lovely road is going
Install a small fan to move the air around. I used a computer fan connected to the power supply for the light. It prevents the frost buildup. Of course, you still have to defrost the frig to due to ice buildup in the freezer.
X2...got my 3 speed fan at Staples for $12. I run it on the slowest setting, least current draw when boondocking.
All RV fidges can ice up due to the fins being so cold, and humidity in the air. Same goes for the freezer. Every couple of months, I turn it off & put the stuff from freezer into the fridge, then leave the freezer door open for about 1-2hrs. I place a bath towel in the bottom to catch the water.
If you are old enough, you will remember the excitement at getting a "new" 'frost-free' refridgerator. No more defrosting the freezer !!
Fulltime livin' & lovin' it in '94 Bounder 32h.
Chevy 454ci Retire in 3yrs.