Daewoo Air Conditioner Error Code 1 blink (8s interval)

The 1 blink (8s interval) fault code on a Daewoo air conditioner indicates a thermistor fault detected on either the indoor coil sensor, the outdoor coil sensor, or both. Thermistors are negative temperature coefficient (NTC) resistors that change resistance in response to temperature, allowing the control board to monitor refrigerant coil temperatures in real time. When the board detects that the sensor circuit has gone open (infinite or very high resistance) or short (near-zero resistance), it interprets this as an out-of-range temperature reading and shuts the unit down entirely to prevent compressor damage or unsafe operation.

The indoor coil thermistor is clipped or pressed directly against the indoor evaporator coil and connects to the main control board via a wiring harness. If the thermistor loses contact with the coil, its clip breaks, or the connector at the board becomes loose or corroded, the circuit can appear open to the control board. Similarly, a shorted thermistor, caused by internal sensor failure or damaged wiring with insulation breakdown, will produce a resistance reading that falls outside the expected operating range. The outdoor coil sensor is subject to harsher environmental conditions and is more prone to moisture ingress and connector corrosion.

The first diagnostic step specified is checking the physical mounting and fixation of the indoor coil thermistor. A displaced or loosely seated thermistor can produce erratic or out-of-range resistance values even when the sensor itself is electrically intact. After confirming proper seating, resistance testing of both thermistors at a known ambient temperature should be performed to determine whether the sensor has failed electrically or whether a wiring or connector fault is responsible.