freezer is cold fridge wont cool

I have a kenmore 26’ side-by-side. Possible model 596.51672100. The freezer is cold but the fridge is warm. I have defrosted the evaporator that was frosted over. The fridge cooled for a day and the evaporator froze over again. I then replaced the board-adapt def that did nothing. I then by passed the thermostat on the evaporator the fridge will not get any colder than 50. The evaporator apperas to be frosting over again. PLease help im lost.