Daewoo Air Conditioner Error Code ON LAMP Blink (8s, 1 times blink)

This blink pattern indicates that the outdoor coil thermistor has been detected in an open or short circuit condition by the control board. The outdoor coil thermistor is a temperature sensor mounted on the outdoor heat exchanger that provides coil temperature data to the system. Importantly, the unit will continue to run despite this fault, but the sensor issue should still be addressed to maintain proper system protection and defrost performance.

The unit is designed to continue operating when this fault is present, so immediate safety risk is low. However, running without accurate outdoor coil temperature feedback can reduce the effectiveness of defrost cycles and coil protection, potentially leading to more serious issues over time. It is best to have the fault repaired in a timely manner rather than ignoring it indefinitely.

A power reset may temporarily clear the displayed fault, but the code will return if the underlying thermistor or wiring problem has not been resolved. The control board will re-detect the open or short circuit condition on the next startup or monitoring cycle and trigger the blink pattern again. Clearing the code without repairing the sensor is not a long-term solution.

A knowledgeable DIYer can inspect the sensor wiring, check connector pins for corrosion, and test the thermistor resistance with a multimeter. If the thermistor itself has failed, replacing it requires sourcing the correct sensor for your specific model and re-routing it to the control board connector. If you are not comfortable working inside the outdoor unit or identifying the correct replacement part, a qualified technician should handle the repair.

If only the thermistor sensor needs replacement, parts typically cost in the range of $15 to $60 depending on the model, with professional labor adding $75 to $150 or more depending on your location. If the wiring harness or control board is also damaged, total repair costs could be higher. Getting a diagnostic quote from a technician before authorizing parts replacement is recommended.