Fridge not cooling freezing up

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Brand:ge
Model Number:gne25jykhffs
Main Symptom:fridge not cooling freezing up
What happens & when:

Error Code (if any):
Parts or tests already tried:defrost unit and sensor
Photos / video link:

Just to verify, the defrost thermostat and the defrost heater assembly (including the wire harness and evaporator sensor) have been replaced? If this is the case, when the evaporator freezes up, is it the entire evaporator or is it a section of it? If a picture could be provided when the evaporator is frozen up, it can help to identify which route we may need to go for diagnosing this issue.

fridge is back up and running but shuts off and starts back up blowing cold. already replaced defrost unit. any recommendations.

What specifically is shutting off? Is it the entire appliance or just the compressor and fans?

just the fan and compressor. lights on