Fridge Forced Defrost Cycle Not Working

Hello, I have a Maytag refridgerator model MBL2258XES1 using the "jazz" control board.

I have the typical freezer cold/fridge warm issue. Parts replaced include the control board, heating element, thermostat. I have using the on board diagnostics to verify operation of the fan and damper/duct (also watched them work properly).

I am still having freeze up issues on the coils due to no defrost cycle happening. Recently I have successfully used the forced defrost cycle to defrost the coils.

My latest problem is that the forced defrost cycle does not initiate. I go through the sequence of steps, but the las t step is to push fridge minus, the display returns to the original settings, and defrost begins. But for me, the display shows two minus signs and the defrost cycle does not begin.

What do the two minus signs indicate, and any suggestions on next steps? I'm considering replacing the control board (again), but I'm about to give up a buy a new refridgerator!