Daewoo Air Conditioner Error Code 1 blink (0.5s interval, 8s cycle)

This blink pattern indicates an open or short circuit fault in the indoor coil thermistor, which is the temperature sensor mounted on the evaporator coil inside the indoor unit. The control board cannot get a valid reading from the sensor, so the unit shuts down completely to prevent damage. The fault points to either a disconnected sensor plug, a damaged wiring harness, or a failed thermistor probe.

The unit will not run when this fault is active, so there is no immediate safety risk from continued operation. The shutdown is a protective response by the control board. Do not attempt to bypass the fault, as the coil thermistor provides important freeze protection and operating without it could damage the evaporator coil or compressor over time.

If only the thermistor probe needs replacement, parts costs are generally in the range of $10 to $40 depending on the specific unit model, with labor adding $75 to $150 for a service call in most markets. If the control board is found to be faulty, parts costs rise considerably, typically $80 to $200 or more. Getting a diagnostic visit from a qualified technician will give you a more accurate estimate for your specific situation.

If the cause is a loose connector or a thermistor that has slipped out of its mounting clip, a knowledgeable DIYer can often resolve the fault by reopening the indoor unit cover, reseating the plug, and securing the sensor back in its clip. However, if the thermistor has failed electrically or the wiring is damaged, replacing components inside the unit is better suited to a qualified technician. Always disconnect power to the unit before opening any panels.

A power reset may temporarily clear the displayed fault, but if the underlying problem with the thermistor or its wiring has not been corrected, the fault will return as soon as the control board re-reads the sensor circuit. A reset alone is not a fix. The sensor, connector, and wiring must be inspected and the faulty component repaired or replaced before the unit will operate reliably.