Your Kitchen Aid refrigerator's cooling issue, despite passing diagnostic tests and having functional sensors and thermistors, suggests a more complex problem. It's noteworthy that the compressor is active and warm, and both the evaporator and condenser fans are working. The absence of ice build-up on the evaporator, especially after the fridge has been at room temperature for over 24 hours, rules out a common cause of cooling issues. Additionally, the cleanliness of the condenser coils and the proper functioning of the condenser capacitor, as indicated by correct microfarad readings, further complicate the diagnosis.
Given these details, a few possibilities remain:
There might be a problem with the refrigerant level or a leak in the system. An insufficient refrigerant charge or a leak can prevent the refrigerator from cooling effectively, even if the compressor and fans are operational.
While the compressor is active and warm, it might not be operating efficiently. Over time, compressors can lose their ability to compress refrigerant effectively, which can lead to cooling issues.
Even if the sensors and thermistors are functioning, there could be an issue with the thermostat or the main control board that's not being detected in standard diagnostics.
Problems in the sealed system, other than refrigerant issues, can be challenging to diagnose and often require professional attention.