Daewoo Air Conditioner Error Code 1 blink (ON lamp, 0.5s pattern)

This blink pattern indicates that the control board has detected an open or short circuit condition in either the indoor coil temperature sensor or the outdoor coil temperature sensor. Because the board cannot read accurate coil temperatures, it shuts down operation completely to prevent damage. Both sensors and their associated wiring need to be tested to identify which component has failed.

No. The unit will not operate while this fault is active, and attempting to force operation without resolving the sensor fault could lead to undetected freeze conditions or compressor damage. The lockout is a protective measure, and the underlying sensor fault should be diagnosed and corrected before returning the unit to service.

If only a coil thermistor sensor needs replacement, parts and labor typically range from around $75 to $200 depending on the specific unit model and local labor rates. If the wiring harness is damaged, repair costs may be similar or slightly lower if a splice repair is possible. A control board replacement, needed only when the board input circuit has failed, can bring total costs into the $200 to $450 range including labor.

A knowledgeable DIYer can check the sensor connectors for looseness or corrosion and reseat them, which sometimes resolves the fault without parts. Testing sensor resistance with a multimeter is also straightforward if you are comfortable working with electrical components. However, if a sensor or control board needs replacement, sourcing the correct part and safely handling refrigerant-side components may require a qualified technician.

A power reset may temporarily clear the displayed fault, but the error will return as soon as the control board attempts to read the faulty sensor again during startup. Resetting does not repair a failed thermistor or damaged wiring. A permanent fix requires identifying and replacing the defective sensor or correcting the wiring fault.