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Error code reference

Daewoo Air Conditioner Error Code 1 times blink

Room sensor open or short circuit; unit continues working with fixed room temperature of 32°C in cooling mode…

Daewoo codesDaewoo air conditioner codes

Room sensor open or short circuit; unit continues working with fixed room temperature of 32°C in cooling mode or 18°C in heating mode.

First step from the service manual

Check room air thermistor (RATH) for open or short condition.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 1 times blink means on a Daewoo air conditioner

The 1 times blink error on a Daewoo air conditioner indicates that the room air thermistor (RATH) has been detected in an open or short circuit condition. The room thermistor is a negative temperature coefficient (NTC) resistor responsible for measuring the ambient air temperature inside the conditioned space. This reading is used by the control board to regulate compressor cycling, fan speed, and overall system output to maintain the target setpoint. When the thermistor circuit reads outside of its expected resistance range, whether due to a broken wire, failed sensor, or short to ground, the control board flags the fault with a single blink pattern.

Despite the fault, the unit does not shut down entirely. Instead, it enters a failsafe operating mode, substituting a fixed temperature value in place of the actual sensor reading. In cooling mode, the system operates as though the room is a constant 32 degrees Celsius, and in heating mode it assumes a fixed 18 degrees Celsius. This means the unit continues running but cannot accurately respond to actual room conditions, which may result in under-cooling, over-heating, or inefficient operation.

Diagnosis starts by inspecting the RATH thermistor itself, its wiring harness, and the connector at the control board. An open circuit typically means a broken sensor element or disconnected wiring, while a short circuit usually points to damaged insulation causing conductors to contact each other or a grounded surface. Resistance testing at the thermistor terminals will confirm whether the sensor is within its specified range at a known temperature.

Source: manufacturer service documentation.

Common causes of 1 times blink

  1. 01

    Failed room thermistor (RATH)

    Part replacement

    The thermistor element itself may have failed internally, presenting an open or out-of-range resistance reading. Testing the sensor with a multimeter at a known ambient temperature will confirm whether it has failed.

  2. 02

    Disconnected or loose thermistor connector

    Wiring / connection

    The wiring connector between the RATH thermistor and the control board may have worked loose, creating an intermittent or permanent open circuit. Inspect the connector at both the sensor and board ends for secure seating.

  3. 03

    Damaged thermistor wiring harness

    Wiring / connection

    Wires leading to the room thermistor can become pinched, chafed, or broken over time, especially near routing clips or panel edges. A visual inspection along the full wire run and a continuity test will identify breaks or shorts.

  4. 04

    Corroded thermistor terminals

    Wiring / connection

    Moisture exposure inside the indoor unit can cause corrosion at the thermistor connector pins, increasing resistance or creating an open circuit. Corroded terminals often appear discolored or pitted and may require cleaning or connector replacement.

  5. 05

    Faulty control board

    Part replacement

    If the thermistor and its wiring test within normal parameters, the input circuit on the control board may have failed, causing it to misread the sensor signal. This is the least common cause and is typically diagnosed after ruling out all sensor and wiring issues.

See the test procedure for each cause

Frequently asked questions about 1 times blink

What does 1 times blink mean on a Daewoo air_conditioner?
A single blink fault code on a Daewoo air conditioner indicates an open or short circuit in the room air thermistor (RATH). This sensor measures ambient room temperature, and when it fails the unit cannot read actual conditions. The system compensates by running on a fixed temperature value: 32 degrees Celsius in cooling mode and 18 degrees Celsius in heating mode.
Can I fix the 1 times blink error myself?
A knowledgeable DIYer can check for a loose or disconnected thermistor connector and reseat it, which may resolve the fault. Testing the thermistor with a multimeter to check for proper resistance is also a straightforward step. Replacing the thermistor sensor itself is a low-complexity repair, but if the control board is the root cause, professional service is recommended.
Is it safe to keep running my Daewoo AC while it shows this error?
The unit will continue to operate in a failsafe mode, so there is no immediate safety hazard. However, because it is running on a fixed temperature assumption rather than real room data, it will not regulate temperature accurately. Extended operation in this mode reduces efficiency and may cause uncomfortable conditions, so the fault should be addressed promptly.
How much does it cost to repair the 1 times blink error on a Daewoo air conditioner?
If only a connector needs to be reseated, the repair can be done at no parts cost. A replacement room thermistor is generally an inexpensive part, typically in the range of $10 to $40 depending on the model. If the control board requires replacement, costs rise significantly, often ranging from $80 to $250 or more including labor.
Will resetting the unit clear the 1 times blink error code?
Power cycling the unit may temporarily clear the displayed fault, but if the underlying thermistor problem persists the error will return once the control board re-detects the open or short condition. A reset alone will not repair a failed sensor, broken wire, or damaged connector. The root cause must be corrected for the fault to stay clear.

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