Samsung RS2556 side by side.
Started with the fridge side freezing food on shelf above "Cool Select Zone Drawer". Then Temp display on Freezer started blinking(indicates a warm up).
Temp in Freezer started to warm significantly, fridge still freezing food. Ran diagnostics through display panel with no leds lighting up. Tried forcing manual defrost a couple times. No difference.

Took apart inside panel on Freezer side and coils frozen up blocking air flow. Hair dryer defrost method and temp returned to normal -4.

Took apart panel in Fridge side and bottom half coils completely frozen, solid block of ice. Hair dryer defrost and fridge temp fine and food not freezing last few days.

Is there a component that controls both defrost heaters? No errors came up in the sensor diags. Find it hard to believe both heaters would go out at same time.