First I searched the net looking for fixes. Several forums pointed out the thermistor, the fan, the heater or the control board. I ohm'd the heater, checked good (94 ohms if I recall). I checked the thermistor and it's resistance didn't seem to match what others were saying it should be. I ordered a replacement from AppliancePartsPros.com. The part was scheduled to arrive in 2-5 days, it arrived the next day! I ordered the fan the next day because I would close the door and the fan wasn't coming on. I decided to check my current fan with a 9v battery and the fan was working. So natural I thought the control board went out, NOT TRUE! The fan takes around 30 seconds to kick on once the door is closed, so I didn't wait long enough my first test. I completely defrosted the coil and the drain, installed the new thermistor. The fridge came down to temp over the next several hours and has been holding for a few days now. Time will tell if this was the issue or not.