CONCERN: Customer reports refrigerator is not getting cold on refrigerator side. DIAGNOSTIC AND CAUSE: Inspected compressor operation, evaporator fan and condenser fan operation, all normal. Found frost build up on evaporator coils. Tested defrost heater for continuity, Found defrost heater, limiter, and thermistor failed. CORRECTION: Replaced defrost heater, limiter, and thermistor. Tested operation, all normal upon completion.