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

This blink pattern indicates the control board has detected a fault in the indoor coil thermistor, the outdoor coil sensor, or both. The board is reading either an open circuit or a short circuit from one of these sensors. Because accurate coil temperature data is required for safe operation, the unit shuts down completely until the fault is resolved.

A power reset may temporarily clear the blink code, but if an underlying sensor fault exists, the error will return once the unit attempts to operate. The control board will re-detect the out-of-range resistance reading and shut down again. A reset is useful for confirming whether the fault is intermittent, but it is not a repair.

If the fix is simply reseating a loose thermistor, there is no parts cost and minimal labor. If a sensor requires replacement, parts typically range from a few dollars to around $30 to $60 depending on the specific sensor and availability. If the control board is at fault, costs rise significantly, generally in the range of $80 to $200 or more including labor.

In some cases, yes. The first thing to check is whether the indoor coil thermistor has simply come loose from its mounting clip on the evaporator coil. Reseating it firmly costs nothing and may clear the fault. However, if a sensor has actually failed or wiring is damaged, replacement parts and basic electrical testing skills are needed, which may be beyond a typical DIY repair.

The unit is designed to stop operating when this fault is detected, so it will not run in most cases. If it were somehow forced to run without valid coil temperature feedback, there would be risk of coil icing or compressor damage. It is best to leave the unit off and resolve the sensor fault before attempting further operation.