My GE Monogram 42 inch side by side is not cooling on either side. No ice build up, compressor is running when I close the door and is not hot. There is no dust on coils. No suction on doors. How do I tell if it is thermostat, fan, or motherboard. (I replaced the motherboard two years ago).
If your compressor up top is running and there is no cooling that’s not good news.
Pull that top trim off and verify that it is the compressor you hear running and not just the fans. Unplug the condenser fan if it makes it easier. If the compressor is actually running (vibrating) and not is warm and the condenser assembly (fins) nearby are also not warm there is no refrigerant being pumped through. Basically the physical act of compressing the r-134a creates significant heat and that heat gets dissipated by the condenser. If there’s no heat there’s no action.
If the compressor isn’t running at all you may have another control issue or possibly an overload or start device issue..