Samsung Air Conditioner Error Code OUTDOOR_RED_FLICKER_GREEN_ON

The OUTDOOR_RED_FLICKER_GREEN_ON error code on a Samsung air conditioner indicates a discharge temperature sensor fault, specifically an open circuit or short circuit condition detected in the sensor circuit. The discharge sensor monitors the refrigerant temperature at the compressor discharge port, which is a critical measurement used by the outdoor unit control board to protect the compressor from overheating and to regulate system operation. When the control board reads a signal that falls outside the expected resistance range for this sensor, it flags the fault and displays this LED pattern on the outdoor unit.

The discharge temperature sensor is a negative temperature coefficient (NTC) thermistor, meaning its resistance decreases as temperature increases. An open circuit condition produces an infinitely high resistance reading, while a short circuit produces a near-zero resistance reading. Both states are invalid operating values that the control board cannot interpret as a real temperature, triggering the fault. The sensor connects to the outdoor unit control board at connector CN51, specifically at pins 3 and 4, which is the first place to inspect during diagnosis.

Common failure points include the sensor thermistor element itself degrading or breaking, damaged wiring harness insulation causing a short to ground or an open wire break, and corroded or loose connector pins at CN51. Environmental exposure in the outdoor unit makes wiring and connector integrity a frequent concern. The control board input circuitry can also fail, though this is less common than sensor or wiring faults.