Freezer works great but fridge temp too high, not

Hi, With the information you supplied I’m going to assume there is an ice build up at the rear of the freezer. Your problem is going to be with your defrost system. I will also assume you have the ability to repair this yourself.
This is going to be one of three problems with your refrigerator, 1st thing to do is remove shelf’s and panel in the back of the Freezer. You may see ice build up on the evaporator, don't worry get a hair dryer and melt the ice.
Next locate the wires for the defrost heater and using a multi-meter/ohms meter test the heater for continuity (it should read infinite) if the defrost heater is bad replace it.
This is what a typical defrost heater looks like:
　
If the heater is good test the defrost thermostat. This should normally be done when the evaporator is still covered with ice since it will only activate at 40f - 50f depending on the thermostat. When tested with the ohms meter at below 40f it will read infinite. It is normally clipped to the upper right of the evaporator and look something like this:
The next possible problem could be the defrost timer. If you have tested the heater and thermostat and they have tested good next find the defrost timer, If your refrigerator has a mechanical one it will either be located inside the control panel in the fridge or behind the panel below the doors. Once you have located it advance the dial until you hear a click. This will initiate the defrost cycle. If your heater begins to get hot this will tell you that your timer has stalled and needs to be replaced. A typical mechanical timer looks like this:
If your refrigerator has a digital defrost timer you should locate the tech sheet. Normally you can find this behind the panel under the doors. It will tell you how to initiate a manual defrost cycle. As before if the heater gets hot you will have to replace the mother board normally located behind a panel at the rear of your refrigerator.
If your fridge is warm and there is no build up of frost/ice on the back panel inside the freezer then you problem is most likely going to be the evaporator fan, have you heard the fan running in the past few hours? if you are not sure pull the panel out to where you can see fan and watch it over the space of an hour to see if it turns. If you don’t see it turning replace the motor. This is what a typical evaporator fan looks like:
Hope this helps. If you have any other questions please feel free to comment again. If you decide to get a repair guy in should not cost you any more then $120 - $200 depending on make/model/problem Good luck & thanks for using Fixya! Mike

That is the first signs of a defrost problem. Most likely the defrost heater and defrost thermostat are the problem. If the rear wall of the freezer is showing a line of frost building now would be a good time to unplug, remove rear panel in freezer and use a hair dryer to remove the ice from the evaporator until you are able to see the defrost heater at the bottom of evaporator. When you are ready and get to that point let me know, Sea Breeze