Refrigerator runs, cools (freezer too), then stops cooling for a few days (freezer stays somewhat cool), then starts cooling again. Help...:(

In these new fangled ice boxs is what you call adaptive defrost control. Instead of the old tried and true defrost timer, brainiacs have decided to use artificial intelligence to determine defrost.
The basic pattern of adaptive defrost is:
COOLING,PRE-CHILL,DEFROST,DWELL,and POST-DWELL.
Hey I ain't making this up. The ADC (adaptive defrost control) Counts the number of times the doors are opened, the total compressor run time, and the length of time the defrost heaters were on during the last defrost. This method supposedly enables the adc to work nice in all kinds of conditions, whether hot and humid or cold and frigid climates. COOLING Mode will remain for an indefinite time or until defrost is determined by the micro-processor. When all systems are go for defrost the adc makes the jump to light speed by going into PRE-CHILL, this brings down the temps in the freezer to off set the defrost operation so that the food temp does not suffer dramatic temp rises. Pretty cool ain't it? If the ice box is in pre chill and the door gets opened then a DEFROST HOLD OFF will jump in and not do a defrost for several hours. If the door is continually opened at the end of 16 hours the adc is gonna defrost that ice box anyway. The defrost period varies but is a maximum time of 45 minutes including when the DWELL kicks in. Dwell is the length of time the ice box stays off AFTER the heater is terminated.
Then The POST DWELL will kick in. The post dwell will fire up the compressor and condenser fan but the inside fans will not run allowing the coils inside to cool down before them fans kick in and she jumps back into Cooling mode. I bet you would like to have a copy of GE's adc repair manual wouldn't you?
TECHNICAL SERVICE GUIDE

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