Amana not chilling

My side-by-side Amana SBD20MW has been working well for over 10 years. Suddenly, the following change has taken place: The freezer is doing its job, but the refrigerator portion is not cooling. Though I am not able to do a temperatur check in the refrigerator section, it does seem to be about the same temperature (feels around 55-60) throughout. No settings have been changed. Inside the refrigerator I hear nothing and do not feel any cool air circulating. In thr freezer I do hear the continual sound of a motor, but feel minimal (if any) air circulating. Under the refrigerator the fan that blows around the drip pan is working and I do feel the air movement. Could it be the evaporator fan motor and, if so, where is it located?

Thanks.

Len