Amana ssd21sw stop cooling freezer side frost in rear wall any sugestions

Defrost cycling problem which will affect cooling the fridge compartment by struck the freezer fan's function.To solve defrost problem:
First, locate the defrost timer which may hidden behindcorners of the fridge at the back bottom, in some models located in the ceilingof the fresh food section or behind the cold control cover. Once you locate thedefrost timer, slowly turn the screw in the middle of the defrost timer withstraight screwdriver until the fridge shuts off. Now it's in defrost. If thedefrost heater(s) starts, replace the defrost timer and defrost thermostat. Ifthe heater(s) does not start, unplug wire cord to check ohm test for continuityof heater. If continuity is there, plug cord wire which gives power 120volts(check specification) to heater. If heater no starts, bypass defrost thermostatby join the 2 wires in the defrost thermostat. If the heater now comes on,replace the defrost timer and defrost thermostat. If the heater itself is bad,replace it. Thanks and hope helpful.