How often does this refrigerator defrost?
This units defrost will vary as it is an adaptive defrost control. The average will be 1 to 2 times daily defrost.
I have no cooling on freezer or refig side , control panel is flashing a 4. I have removed dust from coils. The lower fan is not running.
The flashing 4 error code on the display is an indication that the damper has failed on the unit. You will want to replace the damper assembly 241600906.