Daewoo Air Conditioner Error Code ON LAMP Blink (0.5s, 2 times blink)

The ON LAMP blinking 0.5 seconds on and off twice in a cycle on a Daewoo air conditioner indicates a fault condition involving one or more of three possible issues: an open or shorted outdoor coil sensor, a compressor or compressor electrical component failure, or a refrigerant gas leak. Despite the fault being active, the unit continues to operate, which suggests the control board is logging the error while allowing the system to run in a degraded or partially functional state. This behavior is important for technicians to note because the fault may not cause an immediate shutdown, making it easy to overlook during a casual inspection.

The outdoor coil sensor is a thermistor that monitors the temperature of the outdoor heat exchanger coil. If this sensor has failed open or shorted, the resistance reading will fall outside the expected range, triggering the fault code. A shorted sensor typically reads near zero ohms, while an open sensor reads out-of-range high resistance or no continuity at all. Compressor-related faults in this code category can involve the compressor motor windings, capacitor, or associated relay and wiring. These electrical components must be inspected for proper continuity, capacitance values, and signs of heat damage or arcing.

A refrigerant gas leak is the third possible trigger. Low refrigerant charge causes the outdoor coil to operate at abnormal temperatures, which can produce sensor readings outside normal parameters and stress the compressor. Checking system pressures with a manifold gauge set is the proper method for confirming a leak. Because this code covers three distinct fault categories, a systematic diagnostic approach starting with the sensor, then compressor electrics, then refrigerant charge is recommended to avoid misdiagnosis.