[therobbinsnest]

The freezer is working well but the fridge is only cooling to 50 degrees.

[denman]

You have a problem with the vent which directs cold air from the freezer to the fridge

The people here will need a Model Number since there are a number of different ways to control this vent system

[woodchuck]

If the evaporator coils behind the back panel of the freezer are icing up because of auto defrost failure that will stop the circulation of cold air and eventually affect the freezer too.

check defrost timer, defrost heater, defrost thermostat
Refrigerator Repair Guide: How To Fix a Refrigerator - ACME HOW TO.com

In most of the new units they now have the evaporative defrost control. It senses when to defrost based on how many times and for how long the door is opened. It's more energy efficient but there does seem to be lots of problems with the board.

If frost is not the problem then what denman said.