Fridge doesn't cool

[rambo19997]

I have a Whirlpool arg 774ix fridge that doesn't work.
The problem was that and I solved it replacing capacitors.
Now the fridge works but it doesn't cool.
It cools only if I set the "super" mode so the compressor run continuously for 5 hours.
If I set the max or med or low setting, the fridge and the freezer don't cool.
So I cut the ntc sensor and tested it with multimeter and it works (i think it is 50k ntc sensor because at 20°C the resistance is 50k)
I tested this thermostat thermostat watching this video and it doesn't work but this is not a problem because it is the thermostat for no-frost system.
So what I can do? Is it a motherboard problem?

 

[Micrornd]

The service manual is available at https://elektrotanya.com/whirlpool_arg_774.pdf/download.html
Based on the wiring diagram, it would appear you still have something wrong with the control board.

 

[sb123]

Subcold is great to find your next fridge! They are also perfect for any man cave! Check them out!

 

[PowerEngineer]

I'm wondering if some of your refrigerant might have leaked out.

 

[Paperdoc]

I MAY have had a similar situation recently with my chest freezer. One day I noticed it seemed not cold enough. Next day a little worse. I though the problem was that the lid seal had failed in several places. I could get it to cool down by turning the thermostat setting to max cooling, but then it failed again. In searching for a replacement seal (could not find one) a tech at my appliance parts store said I proably had a bad thermostat, not a lid seal problem. He explained how to remove and replace, then sold me a "universal" unit. That consisted of the dial and thermostat assembly, a mounting bracket system, and the attached long sensor tube. Removal and replacement went exactly as he'd advised, and the unit began operating exactly as it should right away. I bought an inexpensive freezer thermometer to place inside and help me set the new thermostat to the correct point (I aimed for -20C, or just below zero F). It's been just fine for months now.

I suspect that on the old thermostat assembly, the long liquid-filled sensor tube had developed a small crack / leak so it could not send the thermostat assembly enough pressure to indicate a high temperature and trigger cooling. Certainly, as I was removing it, that tube actually did break in two. It is interesting that, in the earlier stages, simply setting the thermostat to max cooling got it working, but only for a day or two before it failed again.

 

[cosmo1212]

Did you end up solving this? Having a similar issue with a Maytag fridge where it only really works on the highest cool setting.