Mitsubishi Air Conditioner Light Blinking Troubleshooting

Table of Contents

Whenever a Mitsubishi air conditioner is experiencing a problem, it blinks some of its lights to alert you about it.

However, a non-technical person like you may have no idea what the blinking of an air conditioner light means and how can you solve it.

For this reason, we have prepared this complete guide for you where you can learn how to troubleshoot the Mitsubishi air conditioner light blinking problems.

Mitsubishi air conditioner light blinks 14 times

Meaning:

If the light of your Mitsubishi air conditioner blinks 14 times, then it means that the power module of your AC is out of order.

Cause of problem:

This problem usually occurs when there is an issue with the power control board. As a result, some key parts of the compressor start malfunctioning.

Solution:

You need to call a qualified HVAC technician to check the following:

  1. Measure the voltage of all the lead wires that are connected to the compressor.
  2. Measure the resistance of all the compressor terminals.
  3. If the power control board has an irreversible problem, then replace it with a new one.

Mitsubishi air conditioner timer light blinks 2 times

Meaning:

When the light of your Mitsubishi air conditioner blinks 2 times, it means there is an outdoor heat exchanger liquid pipe sensor error in your AC.

Cause of error:

The problem occurs due to:

  1. When the connections are poor.
  2. When a wire of the outdoor heat exchanger sensor has broken.

Solution:

This is a technical problem that might not be possible for you to solve at home.

Please call a professional HVAC technician and get your air conditioner assessed by them to resolve the issue.

Mitsubishi air conditioner timer light blinks 6 times

Meaning:

When the light of your Mitsubishi air conditioner blinks 6 times, it means there is a communication error between the indoor unit and the outdoor unit of your AC.

Cause of error:

The problem occurs when:

  1. A connection wire is broken.
  2. The power supply is inconsistent.
  3. There is no power supply.
  4. The circuit boards of the outdoor and indoor units are defective.
  5. The contact is poor.

Solution:

This is a power-related problem that requires technical expertise to be resolved.

Please call a professional HVAC technician to assess your air conditioner and solve this problem.

Mitsubishi air conditioner timer light blinks 5 times

Meaning:

When the light of your Mitsubishi air conditioner blinks 5 times, it means the compressor has overheated.

Cause of error:

The problem occurs when:

  1. The refrigerant level is too low.
  2. A disconnecting valve is closed.
  3. The compressor is overworked due to other problems with the AC.
  4. The vent-pipe sensor is faulty.

Solution:

This is a power-related problem that requires technical expertise to be resolved.

Please call a professional HVAC technician to assess your air conditioner and solve this problem.

If the compressor of your AC is overworked due to poor airflow or other similar problems, you will have to identify and resolve the underlying root problem.

Mitsubishi air conditioner timer light blinks 7 times

Meaning:

When the light of your Mitsubishi air conditioner blinks 5 times, it means there is an error in the outdoor fan motor of your AC. This error is usually related to the DC motor.

Cause of error:

This error occurs when:

  1. The AC plug contact is poor.
  2. The outdoor fan motor is defective.
  3. The outdoor circuit board is faulty.

Solution:

This is a complex problem that requires technical expertise to be resolved.

Please call a professional HVAC technician to assess the defective fan motor in your air conditioner and solve this problem.

Do not attempt to fix the electrical problem on your own if you do not have relevant knowledge & experience. It will help prevent electricity-related injuries and damage to the air conditioner.

Mitsubishi air conditioner’s yellow light is blinking

If the yellow light of your Mitsubishi air conditioner is blinking during the operation, it means there is a wire connection failure.

However, sometimes this light also flashes when another error code is displayed so make sure to check that as well.

Mitsubishi air conditioner’s green light is blinking

Meaning:

If the green light of your Mitsubishi air conditioner is blinking, it means there is one of the following problems with the AC:

  1. There is an unusual spike in power (Over-voltage).
  2. There is a fault in the multi-split settings.
  3. The fan is obstructed and unable to move freely.
  4. The power cord is damaged.
  5. The air filters are clogged.
  6. The refrigerant level is low.
  7. The compressor has failed.
  8. There’s an electric fault.

Solution:

  1. Switch OFF the isolator switch for 25 seconds to reset the air conditioner.
  2. If the fan is being obstructed, you need to remove the obstruction so the fan can move.
  3. Test the continuity of the power cord and if it doesn’t show any, then replace it.
  4. Check the air filters. If they are dirty then replace them or clean them if you are using reusable air filters.
  5. Check the refrigerant levels. If they are low, then call an HVAC expert to check for any possible refrigerant leakages in the system and fix them.
  6. Check the compressor. If it is failing, you’ll have to replace the compressor or get a new air conditioner.
  7. If there is an electric fault, call an HVAC expert to get the AC checked.

Mitsubishi air conditioner left lamp blinks for 0.5 seconds

Meaning:

When the left lamp of your Mitsubishi air conditioner blinks for 0.5 seconds, it means there is a miswiring or serial signal problem in your AC.

Symptom:

The indoor and outdoor units stop operating.

Condition:

No serial signal is received from the outdoor units for 6 minutes.

Solution:

  1. Turn OFF the power.
  2. Does the power supply have a rated voltage of 208/230V AC? If not, check the power supply.
  3. If yes, turn ON the power supply.
  4. Is the voltage between the S1 and S2 terminal blocks equal to 208/230V AC? If not, check the wiring.
  5. If YES, press the emergency operation switch.
  6. Now, does the left lamp of the operation indicator lights up? If NOT, then check if there is any poor contact, disconnected wire, or miswiring problem with the outdoor/indoor connecting wire. If YES, you need to correct it.
  7. Now check if the serial signal error is indicated after 6 minutes. If not, check for any poor contact, disconnected wire, or miswiring problem with the outdoor/indoor connecting wire and fix it.
  8. Next, you need to turn OFF the inverted-controlled lighting equipment. Turn OFF the power supply and then turn it ON again. Press the EMERGENCY OPERATION switch.
  9. Now, is the serial signal error indicated after 6 minutes? If not, you need to reinstall the light or the unit away from each other. On the receiving section of the indoor unit, attach a filter.
  10.  If the serial signal error is indicated after 6 minutes, then turn OFF the power supply.
  11. Check if the outdoor/indoor connecting wires are not connected wrongly. If yes, fix them.

Warning: Miswiring can damage the indoor electronic control board during the operation. Therefore, you need to confirm the wiring is correct before starting the operation.

If you have no idea how this works, then please call an expert HVAC technician to assess the air conditioner, or else you might end up damaging the air conditioner.

Mitsubishi air conditioner left lamp blinks 2 times

Meaning:

There is a problem with the indoor coil thermistor or room temperature thermistor.

Symptom:

The indoor and outdoor units stop operating.

Condition:

The indoor coil or the room temperature thermistor is open or short-circuit.

Mitsubishi air conditioner left lamp blinks 3 times

Meaning:

There is a problem with the indoor fan motor.

Symptom:

The indoor and outdoor units stop operating.

Condition:

No rotational frequency feedback signal is emitted during the operations of the indoor fan.

Solution:

  1. Turn OFF the power supply. Remove the indoor fan motor connector CN211. Remove the vane motor connector CN151 from the electric P.C. board of the indoor. Now turn ON the power supply.
  2. Does the air conditioner operate with a remote controller? Does the OPERATION INDICATOR lamp light up if you press the EMERGENCY OPERATION switch?
  3. If YES, turn OFF the power supply. Measure the resistance between the CN211 indoor fan motor connectors 3 and 4. If you find a short or open circuit, replace the indoor fan motor.
  4. Turn OFF the power supply. Measure the resistance of the horizontal vane motor coil and vertical vane motor coil. If you find a short/open circuit, replace the indoor electronic control PC board and the vertical and horizontal vane motor coil.
  5. However, if the conditions described in point #2 above are NOT satisfied, then you need to turn OFF the power supply. Visually check the pattern side and parts side of the indoor electronic control P.C. board.
  6. Replace the NR11 varistor and F11 fuse if they are burnt and blown. If they are okay, then measure the cement resistance R111 on the indoor electronic control PC board. Is the resistance around 4Ω? If YES, replace the indoor electronic control board. If NOT, then replace the indoor electronic control P.C. board and the indoor fan motor.
  7. However, if only the F11 fuse is blown, you need to measure the resistance between 1 (+) and 3 (-) of the indoor fan motor connector.
  8. If the resistance is 1MΩ or more, replace the F11 fuse. If NOT, then replace the F11 fuse and the indoor fan motor.

Mitsubishi air conditioner left lamp blinks 4 times

Meaning:

There is a problem with the indoor control system.

Symptom:

The indoor and outdoor units stop operating.

Condition:

The data in the nonvolatile memory of the indoor electronic control PC board cannot be properly read.

Solution:

Replace the indoor electronic control PC board to solve this problem.

Mitsubishi air conditioner left lamp blinks 5 times

Meaning:

There is a problem with the outdoor power system of your air conditioner.

Symptom:

The indoor and outdoor units stop operating.

Condition:

Within 1 minute after start-up, the compressor consecutively starts 3 times due to overcurrent protection or startup failure protection.

Solution:

Check the stop valve.

Refer to the outdoor unit service manual and check of inverter/compressor.

Mitsubishi air conditioner left lamp blinks 6 times

Meaning:

There is a problem with the outdoor thermistor of your air conditioner.

Symptom:

The indoor and outdoor units stop operating.

Condition:

The outdoor thermistor is open or short circuit during the operations of the compressor.

Solution:

Check the outdoor thermistor and make sure it is functioning normally.

Refer to the outdoor unit service manual.

Mitsubishi air conditioner left lamp blinks 9 times

Meaning:

There is a problem with the drain pump of your air conditioner.

Symptom:

The indoor and outdoor units stop operating.

Condition:

The float sensor is open and it detects abnormal water levels.

Solution:

  1. Check the characteristics of the float sensor.
  2. Check the drain pump.
  3. Check the drain pipe.
  4. Check the connectors of the drain pump and the float sensor.
  5. Refer to 9.6E, check of float sensor.

Mitsubishi air conditioner left lamp blinks 7 times

Meaning:

There is a problem with the outdoor control system of your air conditioner.

Symptom:

The indoor and outdoor units stop operating.

Condition:

The data in the nonvolatile memory of the inverter PC board or outdoor electronic control PC board cannot be read properly.

Solution:

  1. Replace the inverter P.C. board.
  2. Or replace the outdoor electronic control PC board.
  3. Refer to the outdoor unit service manual.

Mitsubishi air conditioner left lamp blinks 14 times

Meaning:

When the left lamp of the operation indicator blinks 14 times, it means the system has detected an abnormality other than all those mentioned above.

Symptom:

Indoor and outdoor units stop operating.

Condition:

The system detects an abnormality other than all those mentioned above.

Solution:

Use the failure mode recall function to check the abnormality in detail.

Mitsubishi air conditioner RUN light ON, 1-time flash

Description of problem:

When the RUN light is ON and flashes 1 time, it means there is a current cut.

Cause of error:

The problem occurs due to:

  1. Locking of the compressor.
  2. Open phase on compressor output.
  3. Closed service valve.
  4. Short circuit on power transistor.

Mitsubishi air conditioner RUN light ON, 2-time flash

Description of problem:

There is a problem with the outdoor unit of your AC.

Cause of error:

The problem occurs when:

  1. The power transistor is broken.
  2. The compressor wire is broken.
  3. The discharge pipe sensor wire is broken.
  4. The connector connection is poor.
  5. There is a blockage in the compressor.

Mitsubishi air conditioner RUN light ON, 3-time flash

Description of problem:

This happens when there is an overcurrent.

Cause of error:

The main causes of this error are overcharge and overload operation.

Mitsubishi air conditioner RUN light ON, 4-time flash

Description of problem:

There is an error in the power transistor.

Cause of error:

It happens when the power transistor is broken.

Mitsubishi air conditioner RUN light ON, 5-time flash

Description of problem:

The compressor of your air conditioner has overheated.

Cause of error:

The problem occurs when:

  1. There is a shortage of gas.
  2. The discharge pipe sensor is defective.
  3. The service valve is closed.

Mitsubishi air conditioner RUN light ON, 6-time flash

Description of problem:

There is an error in signal transmission.

Cause of error:

  1. The power supply is defective.
  2. The signal wire is broken.
  3. The indoor & outdoor unit boards are defective.

Mitsubishi air conditioner RUN light ON, 7-time flash

Description of problem:

There is an error in the outdoor fan motor.

Cause of error:

  1. The fan motor is defective.
  2. The connector’s connection is poor.

Mitsubishi air conditioner RUN light-ON keeps flashing

Description of problem:

The RUN light keeps flashing due to cooling high-pressure protection.

Cause of error:

  1. Overcharge of gas.
  2. Indoor unit short circuit.

Mitsubishi air conditioner RUN light 2-time flash

Description of problem:

The rotor is locked.

Cause of error:

  1. The compressor is defective.
  2. Open phase on the compressor.
  3. The outdoor unit board is defective.

Mitsubishi air conditioner RUN light 1-time flash

Description:

The service valve is closed.

Cause of error:

This happens when the service valve is closed.

Mitsubishi air conditioner RUN light keeps flashing, TIMER light 1-time flash

Description of problem:

There is an error in the outdoor temperature sensor.

Cause of error:

  1. The outdoor sensor wire is broken.
  2. The connector’s connection is poor.

Mitsubishi air conditioner RUN light keeps flashing, TIMER light 2-time flash

Description of problem:

There is an error in the outdoor heat exchanger fluid pipe sensor.

Cause of error:

  1. The connector’s connection is poor.
  2. The wire of the heat exchanger fluid pipe sensor is broken.

Mitsubishi air conditioner RUN light keeps flashing, TIMER light 4-time flash

Description of problem:

There is an error in the discharge pipe sensor.

Cause of error:

  1. The connector’s connection is poor.
  2. The wire of the discharge pipe sensor is broken.

Mitsubishi air conditioner RUN light keeps flashing, TIMER light 5-time flash

Description of problem:

There is an error in the suction pipe sensor.

Cause of error:

  1. The connector’s connection is poor.
  2. The wire of the suction pipe sensor is broken.

Mitsubishi air conditioner TIMER light ON, RUN light 1-time flash

Description of problem:

The heat exchanger sensor 1 has an error.

Cause of problem:

  1. The connector’s connection is poor.
  2. The wire of heat exchanger sensor 1 is broken.

Mitsubishi air conditioner TIMER light ON, RUN light 2-time flash

Description of problem:

The room temperature sensor has an error.

Cause of problem:

  1. The connector’s connection is poor.
  2. The wire of the room temperature sensor is broken.

Mitsubishi air conditioner TIMER light ON, RUN light 3-time flash

Description of problem:

The heat exchanger sensor 3 has an error.

Cause of problem:

  1. The connector’s connection is poor.
  2. The wire of heat exchanger sensor 3 is broken.

Mitsubishi air conditioner TIMER light ON, RUN light 5-time flash

Description of problem:

There is an active filter voltage error.

Cause of problem:

The power supply is defective.

Mitsubishi air conditioner TIMER light ON, RUN light 6-time flash

Description of problem:

The indoor fan motor has an error.

Cause of problem:

  1. The fan motor is defective.
  2. The connector’s connection is poor.

Mitsubishi air conditioner TIMER light ON, RUN light 7-time flash

Description of problem:

The refrigerant is insufficient.

The service valve is closed.

There is an error in the heat exchanger sensor 1.

Cause of problem:

  1. The refrigerant is insufficient, possibly due to leakage.
  2. The service valve is closed.
  3. The wire of heat exchanger sensor 1 is broken.
  4. The connector’s connection is poor.

Mitsubishi air conditioner POWER lamp flashes 3 times

Meaning:

If the power lamp of your AC flashes 3 times, it means the indoor fan is not working.

Solution:

  1. Turn OFF the power supply.
  2. Is there an object obstructing the rotation of the fan? If YES, remove it so the fan can move freely. If NOT, follow the next steps.
  3. Turn ON the power supply and wait for 5 seconds. Now press the EMERGENCY OPERATION switch.
  4. Now you need to measure the supply voltage within 12 seconds after pressing the EMERGENCY OPERATION switch. If 12 seconds have already passed, you need to turn OFF the power, then turn it ON and measure the supply voltage as per the instructions below.
  5. Measure the voltage between CN211, 1(+) and 3(-) and also between 5(+) and 3(-).
  6. Is there around 325VDC voltage between CN211 1(+) and 3(-)? And does the voltage between CN211 5(+) and 3(-) rises to the range of 3 to 6VDC within 12 seconds after the EMERGENCY OPERATION switch is pressed?
  7. If YES, replace the indoor fan motor.
  8. If NOT, replace the indoor electronic control P.C. board.
  9. Measure the voltage between CN211; 6(+) and 3(-) while the fan motor is rotating.
  10.  Is it unchanged holding 0 or 15VDC? If YES, replace the indoor fan motor. If NOT, replace the indoor electronic control P.C. board.  

Mitsubishi air conditioner ALL lamps flash ON & OFF every 0.5 seconds

In this situation, the indoor and outdoor units stop operating.

Solution:

  1. Turn OFF the power supply.
  2. Is the horizontal vane stopper locked to the indoor unit correctly?
  3. If NOT, you need to relock the stopper of the horizontal vane to the indoor unit.
  4. Turn ON the power supply now.
  5. Are all lamps flashing? If NOT, the problem is solved.
  6. If YES, turn OFF the power supply.
  7. Check the continuity of the interlock switch by measuring the resistance of the connector (1) – (2) connected to CN1R1 on the indoor electronic control PC board.
  8. Is the resistance there 0Ω? If YES, replace the interlock switch (fan).
  9. If NO, replace the indoor electronic control P.C. board.

Mitsubishi air conditioner PLASMA lamp flash 2 times

Solution:

  1. Turn ON the power supply.
  2. Does the PLASMA lamp flash 2 times and the unit stops working?
  3. If YES, replace the indoor electronic control PC board.
  4. Now while pressing the OPERATION SELECT & TOO COOL buttons on the remote controller at the same time, you need to press the RESET BUTTON.
  5. Now release the RESET button first and then release the other 2 buttons.
  6. Press the OPERATE/STOP (ON/FF) button and the set temperature is displayed.
  7. Head the remote controller towards the indoor unit and press the PLASMA button once.
  8. Does the PLASMA lamp stay OFF or it continues to blink?
  9. If it continues blinking, replace the PLASMA POWER P.C. board.
  10. If it stops blinking, the problem is solved.

Mitsubishi air conditioner blue light blinking

Meaning:

If the blue light of your Mitsubishi AE-200A air conditioner is blinking, it means that the software of your unit is being updated.

Check procedure & remedy:

Once the update is over, the LED blue light will turn OFF.

Mitsubishi air conditioner pink light blinking

Meaning:

If the pink LED light of your Mitsubishi AE-200 air conditioner is blinking, it means the software update of the unit has failed.

Cause of error:

  1. The update could not be done due to an unexpected erroneous operation.
  2. The update file is wrong or corrupted.
  3. The USB memory device is inserted wrongly.
  4. The USB memory device is not compatible with your air conditioner unit.
  5. The USB memory device is damaged.
  6. The USB memory device was removed during the update and then reinserted quickly.

Check procedure & remedy:

  1. Try performing the update again.
  2. Make sure the update file is working and compatible with your unit.
  3. Make sure the USB memory device is connected properly and is compatible with your AC unit.

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