When I arrived the back panel inside the freezer has massive frost buildup on it. I unplugged the refrigerator from the wall outlet, then ohm tested the defrost thermostat while it was frosty and the heating element, both ohm tested good.

I ordered and replaced the adaptive defrost control board and it worked great!

Before the adaptive defrost control board is replaced its a must to defrost the entire evaporator coil from top to bottom.

Here is the adaptive defrost control board for this model:
W11227239 Adaptive Defrost Control Board
W11227239

Jake