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Error code reference

Daewoo Air Conditioner Error Code 0 blinks (continuous ON blink)

Room sensor open or short

Daewoo codesDaewoo air conditioner codes

Room sensor open or short — unit continuously works but fixes room temperature to 32°C in heating mode.

First step from the service manual

Check room sensor for open or short circuit. Open: Micom input voltage 0~0.3V, Short: Micom input voltage 4.7~5.0V.

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

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What 0 blinks (continuous ON blink) means on a Daewoo air conditioner

The continuous ON blink pattern on a Daewoo air conditioner signals a fault with the room temperature sensor (also called the indoor air thermistor). This sensor feeds real-time room temperature data to the microcomputer (micom) control board, allowing the unit to regulate heating and cooling output. When the micom detects that the sensor signal is outside its expected voltage range, it registers the fault and enters a failsafe mode. In heating mode, this failsafe locks the target room temperature to a fixed 32°C, meaning the unit continues to operate but loses its ability to respond to actual room conditions or user-set temperatures.

The micom distinguishes between two failure types based on the voltage it reads at the sensor input pin. An open circuit condition, where the sensor wiring or sensor element has broken continuity, produces a micom input voltage in the range of 0 to 0.3V. A short circuit condition, where the sensor leads or internal sensor element have fused together or contacted each other, produces a voltage in the range of 4.7 to 5.0V. Under normal operation, the thermistor voltage sits between these extremes as resistance changes with temperature. Readings outside the 0.3V to 4.7V window confirm a sensor fault.

Common causes include physical damage to the sensor element, corroded or loose connector pins at the sensor harness, or wiring that has been pinched, abraded, or exposed to moisture. Because the unit continues running in failsafe rather than shutting down, the fault can go unnoticed until users realize the room temperature is not being controlled accurately. Prompt diagnosis and sensor replacement will restore normal temperature regulation.

Source: manufacturer service documentation.

Common causes of 0 blinks (continuous ON blink)

  1. 01

    Failed room temperature sensor (thermistor)

    Part replacement

    The thermistor element inside the sensor degrades over time and can develop an open or short internally. This is the most frequent root cause and will produce the out-of-range micom voltage readings described in the fault criteria.

  2. 02

    Corroded or disconnected sensor connector

    Wiring / connection

    Moisture or vibration can loosen or corrode the connector pins between the sensor harness and the control board, interrupting the signal. Inspect the connector for oxidation, bent pins, or a partial disconnect before replacing the sensor.

  3. 03

    Damaged sensor wiring harness

    Part replacement

    The wiring between the sensor and the micom board can be pinched by panels during reassembly or abraded by sharp edges, causing an open or short in the circuit. Visually trace the full harness length looking for cuts, pinches, or melted insulation.

  4. 04

    Moisture or contamination on the sensor or board

    Wiring / connection

    Water ingress near the sensor mounting location or at the control board terminal can create a leakage path that produces abnormal voltage readings. Check for visible moisture, water staining, or corrosion at both the sensor body and the board connector.

  5. 05

    Faulty micom control board

    Part replacement

    If the sensor and wiring both test within normal resistance and continuity specifications, the micom input circuit itself may be damaged and reading incorrect voltages. This is the least common cause and should be diagnosed only after ruling out the sensor and harness.

See the test procedure for each cause

Frequently asked questions about 0 blinks (continuous ON blink)

What does 0 blinks (continuous ON blink) mean on a Daewoo air_conditioner?
The continuous ON blink pattern indicates the room temperature sensor has been detected as open or short circuited. The micom control board reads an input voltage either below 0.3V (open) or above 4.7V (short), both of which are outside the valid sensor range. As a result, the unit enters failsafe mode and fixes the room temperature target to 32°C during heating operation rather than responding to actual room conditions.
Can I fix the continuous ON blink fault myself on a Daewoo air conditioner?
A knowledgeable DIYer can check the sensor connector for corrosion or looseness and inspect the wiring harness for visible damage without specialized tools. Measuring voltage at the micom sensor input pin requires a multimeter and basic electrical knowledge. Replacing the room sensor itself is a straightforward part swap, but if the control board is the underlying cause, board replacement is more involved and may warrant a qualified technician.
Is it safe to keep running my Daewoo air conditioner when this fault is active?
The unit will continue operating in failsafe mode, so it is not immediately dangerous. However, because the room temperature is fixed at 32°C in heating mode rather than being regulated by actual sensor feedback, the system cannot respond correctly to real room conditions. Running in this state for extended periods wastes energy and prevents accurate temperature control, so prompt repair is recommended.
How much does it cost to repair the continuous ON blink fault on a Daewoo air conditioner?
If only the room temperature sensor needs replacement, parts typically range from around 10 to 40 dollars depending on the specific model. Professional labor for diagnosis and sensor replacement generally adds 60 to 150 dollars. If the control board requires replacement, total repair costs can range from 150 to 400 dollars or more depending on part availability and labor rates in your area.
Will resetting my Daewoo air conditioner clear the continuous ON blink fault?
A power reset will temporarily clear the fault indication, but the error will return immediately if the underlying sensor problem has not been corrected. Because the micom checks the sensor voltage at startup and during operation, any open or short circuit condition will trigger the failsafe mode again as soon as the unit restarts. The fault will only stay cleared after the defective sensor, wiring, or connector has been repaired or replaced.

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