Mitsubishi Electric aircon blinking light: what each blink means

What does a blinking light on a Mitsubishi Electric aircon mean?

A blinking operation lamp on a Mitsubishi Electric Starmex means the unit found a fault and stopped. Count the blinks between the pauses: each count points to an area, such as 2 for a temperature sensor, 3 for the indoor fan motor and 5 for the outdoor unit's power system. A technician confirms the part.

Key takeaways

• Count the blinks: the lamp blinks a set number of times, pauses for about two and a half seconds, and repeats.
• Low counts are indoor, 5 and up are outdoor: 2 to 4 blinks point to the indoor unit, 5 to 7 and 14 to the outdoor unit.
• All lamps blinking together is the vane: the flap at the air outlet is not seated, so both units stop.
• Outdoor power and gas faults mean stop: 5 blinks, 14 blinks and codes such as PL or UP can damage the compressor if the aircon keeps running.

In the video above, a Mitsubishi Electric Starmex System 3 (outdoor unit MXY3G28VA) at Ashi Foot Reflexology in Katong was reported blinking by the staff. We counted 7 blinks, which points to the outdoor circuit board. We checked the control board, and further troubleshooting traced the fault to a failed relay; we replaced it with an original Mitsubishi Electric part. Read the full Katong repair.

How do I read the blinks?

1. Stand in front of the indoor unit and look at the operation lamp: the upper lamp, or the left one on some models.
2. Count the blinks. The lamp blinks quickly a set number of times, goes off for about two and a half seconds, then repeats.
3. Count at least two rounds to be sure of the number.
4. Check the pattern: a steady blink with no pause, or every lamp blinking together, means something different from a count.
5. Write down the count and the model number, which is on a sticker on the side of the indoor unit.
6. Switch the aircon off and find the count in the list below.

Mitsubishi Electric blinking light list

This list follows Mitsubishi Electric Singapore's own error code sheet and the Starmex service manuals, in our own words. It is for Starmex inverter indoor units, on a single split or a System 2, 3 or 4 multi-split. Older or other series can differ slightly, so treat each row as a guide to where the fault sits, not a diagnosis.

"Reset once" means: switch the aircon off at its isolator, wait three minutes, switch it on. "Off" means leave the aircon switched off until it is checked.

Starmex inverter units

Older non-inverter units

Older non-inverter Starmex models use a shorter table: 2 blinks for a temperature sensor, 3 for the indoor fan motor and 4 for the indoor circuit board, as above. 14 blinks means a refrigerant circuit fault, such as low gas or an outdoor fan that has locked. Leave it off until it is checked.

Remotes with a CHECK button: two-digit codes

Some Mitsubishi Electric remotes have a small CHECK button. Switch the remote off, stand within two metres of the indoor unit, point the remote at it and hold CHECK with a pen tip until the unit beeps and a code shows on the remote. "00" means no fault; "-" means the remote got no reply, so move closer and try again. Press any button to leave. Many Starmex remotes sold in Singapore have no CHECK button; on those, use the blink count.

Outdoor board lights, for technicians

On System 2, 3 and 4 outdoor units (MXY), the outdoor circuit board has a red and a yellow LED. Both lit steadily means the outdoor unit sees no fault; blink patterns tell a technician which part to test. Mitsubishi Electric Singapore's sheet above has the full LED table. Owners should not open the outdoor unit: the board carries mains power.

Your pattern is not here, or the lamp is blinking right now? Message Luna on WhatsApp with the blink count and your model number, and we will tell you the next step.

How we trace a blinking Starmex

The blink count tells us where to start, not which part to buy. We confirm the area with the count, test the parts there, and only then order an original part. On the Katong job in the video, 7 blinks sent us to the outdoor boards, and testing there found the failed relay before anything was ordered; the replacement took about three hours. For how these units are built, read our technician's view of Mitsubishi Electric Starmex.

Why one room or every room?

On a System 2, 3 or 4, several indoor units share one outdoor unit. Two to four blinks belong to that one room. Five to seven blinks, 14 blinks and the steady blink usually stop every room on that outdoor unit, because they all depend on it.

Can I reset a blinking Mitsubishi aircon myself?

You can try once, for the patterns the list marks "Reset once". Count the blinks first, so you still have them if the lamp goes off. Then switch the aircon off at the isolator switch, wait three minutes and switch it back on.

If the fault was a one-off, such as a brief power dip, the unit may run normally. If the same blinks return, the fault is real. Resetting it over and over hides the symptom while the cause gets worse, for example a compressor running short of gas; our post on aircon gas leak signs explains why low gas always means a leak somewhere.

What it costs

The cost depends on what the blinks point to. We diagnose first and only replace what has failed.

Repairs carry our warranty from 180 days.

When to call a technician

Call us if:

• the same blinks come back after one reset
• the count is 3 or more, or the remote shows a code marked "Off" above
• the unit is not cooling, is leaking water, or is making new noises along with the blinking
• you cannot make out the count

Other brands blink their own way: see our lists of Daikin error codes and Panasonic error codes. Tell us the blink count when you get in touch; it helps us bring the right parts and tools for aircon repair and troubleshooting. You can book online in under a minute, or message Luna, our AI assistant, on WhatsApp at any hour.