Refrigerator not cooling, force run works fine.

Hi, I have a Samsung RF22M9581SG. All of sudden the refrigerator is not cooling. The freezer and ice maker work fine. The displayed temperature is at desired value (3C) but the actual is 19C.

Here is a list of things I have tried.

• Power reset - the temperature now shows correctly as 19C, but it is not cooling
• Force defrost & power off for 24 hours to let it defrost - not helping
• Reset to factory settings - not helping
• Checked all the settings, changing the temperature setting, enabling or disabling "Power cool" - not helping
• "Cooling off" is deactive
• I opened the back panel and there is no ice at all. The coil is not cool at all.
• Both sensors give me ~5k ohm reading at around 20C
• The fan moves smoothly.
• If I do a force run (FF r), everything seems working. The coil gets cooled down and the fan works at the highest speed. The temperature is going down.
• Once I stopped the force run, it is not working anymore.
• I did see "fridge fan highest" from the status from time to time.
• I only saw "fridge valve on" when I enabled FF r. I assume this is in regard to the valve to the coil
• Self diagnostic does not show any error.

I am not sure what I should check next. Any advice will be highly appreciated.

Thank you.