GE Profile Model PSB42LGRBWV Whistling noise coming from freezer evaporator fan. Changes in pitch. Had control board AND freezer evaporator fan replaced with new parts by authorized GE repair tech. Still whistles!!!! What's next???

We had a lot of inquiries with what we call whistling appear to be from different problems which here below:

First case, whistling sound is what we call "Ghosting". To get rid of this sound one needs to put more gas into the system, but more gas will create the suction pipe to frost up and reducing the gas level will create less cooling. The best solution were to full regenerating Freon gas mean remove it filter it out and charge it back. However this will cost more $100 and basically you can leave it and live with it. No harm is created only the sound appears while running.

Second case were with a loud whistling, like a dying bird stuck in your freezer, you likely have a faulty freezer fan motor and you need to be replaced

Third case were with a lower pitched, sort of gentle whistling sound then you have an issue with the door damper, which allows the air flow from the freezer into the refrigerator. And assuming you don't have any cooling problems, it may simply be a normal occurrence, as some makes and models open and close this damper door automatically, and when it is closed, can sometimes cause a low whistling noise

Fourth case was making a moaning, whistling noise coming from just above the ice maker. It happened when the fan speed changed. We found out that the motherboard was probably defective.
Rather than go thru GE, you can found a new one online for 66 bucks. You can replaced it in about ten minutes and it's all fixed.

Fifth the evaporator fan motor should not change speeds in less than 1 minute of time. The fan motor has two speeds. Usually this is a indication of a failing main board. If you have a meter you can do a voltage check at the J-2 connector on the board. Check for 13VDC between pins J2-3 and J2-8 and 8 to 13VDC between J2-3 and J2-4. If this voltage stays steady, your problem lies in the evaporator fan motor. If this voltage drops out or fluctuates, it's more than likely the board need to be replaced