Daewoo Air Conditioner Error Code 1 blink (ON lamp, 8s pattern)

The 1 blink ON lamp fault code on a Daewoo air conditioner signals a fault in the room temperature sensor circuit. This sensor is a negative temperature coefficient (NTC) thermistor located in the indoor unit, responsible for reading the ambient room temperature and sending that data to the control board. When the control board detects a resistance value outside the expected range, it interprets the condition as either an open circuit (broken or disconnected sensor) or a short circuit (shorted sensor leads or failed thermistor). The unit will continue to operate rather than shutting down, but it locks the assumed room temperature at a fixed 32°C in cooling mode to maintain some level of function.

Because the control board is working from a fixed 32°C reference instead of actual room temperature, the unit cannot modulate cooling output based on real conditions. This means the compressor may run longer than necessary or the system may not reach the desired setpoint accurately. While the unit remains operational, efficiency and comfort are compromised during this fault state. The blinking pattern repeats on the ON indicator lamp in an 8-second cycle, which is how the control board communicates this specific fault without a digital display.

Diagnosing this fault begins with inspecting the room temperature sensor itself. The thermistor should be tested for resistance at a known temperature and compared against the specified resistance curve. A reading of zero ohms indicates a short, while infinite resistance points to an open circuit. Wiring between the sensor and the control board should also be inspected for corrosion, pinched leads, or disconnected connectors, as these can produce the same fault symptoms even when the thermistor itself is intact.