I am encountering the classico Samsung refrigerator issue:
freezer is cold, but frige is warm.

I have done the following:
For first try, I have removed the back panel of the freezer and melt away
the ice build up on the evaporator and the refrigerator worked for about a day
then the ice build problem started again.

I then,
1. Removed back panels on the freezer side again.
2. Tested the evaporator fan with 12V, it is working. I put it back in the
freezer, and fan ran when I powered on the refrigerator, I saw it running and
stopping when I opened the freezer.
3. Tested two temperature sensors, both exhibited 4K Ohm at about 85F and 11K Ohm
in the ice water, both appear to work.
4. Measured the resistance of heater, it was about 49.5 Ohm, no open circuit here.
5. I measured the resistance of thermal fuse, Ohm meter beeped, therefore, the resistance is negligible.
6. Cooling fan on the condenser ran, the condenser was quite hot, but the consender coil
was only luke warm.
7. Freezer evaporator coil got cold quicky once I applied the power.

During the second test, the temperature display on the frige side first show one blinking bar
at the bottom, after a while, another blinking bar on the top show up, two blinking bars on the
temperature display of the frige. There was no blinking bar on the freezer side.

It appears to me that the defrost didn't turn on but most of the culprits have been ruled out
except the control PCB board. I would love to hear some words of wisdom on trouble shooting
this two year old refrigerator.

I have ordered a service manual and hopefully, it will arrive soon.
Thank you for your suggestions.