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See the below link for a service manual.
Download Amana BX Refrigerators.pdf
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[COLOR="Blue"]I pulled off the grill in the front and all I can see is a red dial on the bottom right on the face of a steel box which I am able to turn CW.[/COLOR]
I think you are looking at the defrost timer cam (item 342 in the Machine Compartment section). It is used to force a manual defrost.

After viewing some possible solutions on this site and elsewhere I was hoping this was due to ice build-up in the freezer section blocking the air vents, but this is not the case; there is only a slight film of ice against the back wall of the freezer with nothing appearing to be blocked. The freezer contents are rock-solid, and the fan seems to be fine, but there is no air circulation in the fridge compartment as far as I can tell.


[COLOR="Blue"]After some further reading I think it may be the condenser fan,[/COLOR]
It may be just semantics but to be sure we do not get confused.
The condenser fan is the fan down by the compressor at the back. it cools the condenser coils and the compressor.
The evaporator fan is in the freezer. It is the fan that circulates cold air in the unit.
The compressor, the condenser fan and the evaporator fan should all be on at the same time as they are wired in parallel.

You may have a defrost problem re: the evaporator coils are iced/frosted over to the point that the fan cannot pull air through them and circulate it in the unit.

Mark a spot on the timer cam and the machine frame. Then leave it an hour or so to see if the cam moved. If not you have a timer problem. Note that the timer only advances when the compressor and fans are on.
If it turns then try forcing a defrost cycle. With luck you will not have to pull the freezer's rear cove as this is a bit of a pain but you may end upo having no choice.
Turn the cam till the compressor and fans go off, you are now in defrost.
You may be able to see the defrost heater glow or hear the water melting/sizzling with the rear cover on.

Another possibility is the damper (item 261 in section 02). This device has it's own thermostat and regulates the amount of cold air entering the fresh food section.