Hello Dave,
Check the Bake (bottom) heating element for continuity.
If the heating element if good, replace the oven control board.
The fan on the back wall in the oven is for convection only and should work only when you use the convection cooking.
- The control board AP2127092
Here are the breakdown diagrams and Parts for Frigidaire FED387CHSC Range - AppliancePartsPros.com
Gene.