Daewoo Air Conditioner Error Code ON lamp continuous blink

The ON lamp continuous blink code means the micom has detected an open or short circuit in the room temperature sensor circuit. Because the unit cannot get a valid temperature reading, it defaults to running heating mode at a fixed 32°C rather than shutting down completely. The micom input voltage is used to distinguish between an open circuit (0 to 0.3V) and a short circuit (4.7 to 5.0V), which helps direct the repair to either the sensor, wiring, or connectors.

The unit will continue to operate in heating mode at a fixed 32°C despite the fault, so it is not completely non-functional. However, running it in this state means there is no accurate temperature control, and the unit may overheat a space or run continuously without cycling properly. It is advisable to address the sensor fault promptly to restore normal temperature regulation.

A power reset will not permanently clear this fault because the underlying sensor circuit problem remains. The micom will detect the abnormal input voltage again on startup and resume the blink pattern. The error will only clear once the room temperature sensor circuit is repaired and the micom input voltage returns to its normal mid-range operating level.

Start by measuring the micom input voltage from the room temperature sensor circuit. A reading below 0.3V points to an open circuit, while a reading above 4.7V indicates a short. Check the sensor connector for loose pins or corrosion, inspect the wiring for damage, and test the thermistor resistance directly. If the sensor has failed, replacing it should clear the fault once the circuit returns to its normal operating range.

If only the room temperature sensor needs replacement, parts costs are typically in the range of $10 to $40 depending on the specific sensor and availability. If a technician is needed for diagnosis and repair, total service costs including labor generally range from $75 to $200. Control board replacement, if required, would cost more, typically in the $100 to $300 range for parts alone.