[Travis]

Hi,
Our freezer stays cold, but keeps developing frost in it. Fridge temp goes up and down. I have taken it apart and defrosted it and left it unplugged for a day and then restarted it. At first, it runs normally. The motor runs and shuts off and the temp in the fridge and freezer remain at the set temp. Within a week or so, the motor starts to run more and more and the temp in the fridge first goes lower say 32 and then does a complete turnaround and starts going up to 50-60 degrees. I have narrowed this problem down to 3 parts that are posted in the general repair section of this website, but wondered if we could narrow it down with me providing more details. Please help.
Thank you,
Travis

[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

Frost in other parts of freezer would be caused by excess moisture entering the unit through bad door gasket, and frequent door opening.

[Travis]

Thank you for your advice. The problem is definitely only behind the rear panel of the freezer with some frost on the side facing in. No other place in the freezer has any frost at all. I have found the panel with the parts you mentioned and opened it. Now I will look at some parts.
Thanks again.