LG Aircon Blinking Light Patterns

Reference table for common LG blink patterns. Use this to identify likely fault classes and narrow what to check next.

Before you use this tool

This is a blink-pattern guidance table, not a model-exact diagnosis. Pattern meaning can vary by controller and series. If your controller shows a direct code (for example `CH21`, `U4`, `E6`), use the error-code guide for a faster match.

Safety warning

Stop using the unit and contact a technician if the breaker trips repeatedly, you smell burning, see sparks, hear loud electrical buzzing, or water is leaking from places it normally should not.

LG pattern table

Includes common SG residential blinking-light patterns with likely fault classes and typical causes.

Continuous or repeating blink

After operation stops, green/blue lamp blinks periodically for about 5 to 15 minutes with weak airflow

Auto-drying cycle indication (post-operation moisture purge)

Details

Pattern ID: GREEN_BLUE_BLINK_AUTODRY

Pattern type: Persistent blink

Category: General

Indicator: Indoor unit

LEDs: GREEN, BLUE

Typical causes

Auto-drying function enabled
Post-stop moisture removal routine

Continuous or repeating blink

Timer light blinks while top/bottom unit LEDs blink in count combinations to indicate fault type

Blink-count decoding scheme described for LG indoor indicators

Details

Pattern ID: TIMER_BLINK_DUAL_LED_COUNT_SCHEME

Pattern type: Persistent blink

Category: System

Indicator: Indoor unit

LEDs: TIMER, TOP, BOTTOM

Typical causes

Model-specific fault signalling active
Indoor/outdoor or compressor-side abnormality
Stored protective error condition

Continuous or repeating blink

Timer/error indication appears with P2 or FL drain-pan-full fault behavior

Drain-pan full protection indication

Details

Pattern ID: TIMER_BLINK_P2_FL_DRAIN

Pattern type: Persistent blink

Service code (reference only): P2/FL

Category: Indoor

Indicator: Indoor unit

LEDs: TIMER

Typical causes

Drain pan full/water level trigger
Drain path obstruction
Water removal issue causing protective stop

Blink count: 2repeating cycle

Top LED blinks 2 times and bottom LED blinks 1 time in a repeating cycle

Compressor/inverter overcurrent malfunction indication

Details

Pattern ID: TOP2_BOTTOM1_CH21

Pattern type: Blink count cycle

Blink count: 2

Service code (reference only): CH21

Category: Inverter

Indicator: Indoor unit

LEDs: TOP, BOTTOM

Typical causes

Inverter DC overcurrent condition
Compressor electrical loading fault
Drive/control board abnormality

Continuous or repeating blink

On supported cassette models, yellow lamp blinks periodically after stop until auto-drying ends

Auto-drying indication variant on certain LG system models

Details

Pattern ID: YELLOW_BLINK_AUTODRY_CASSETTE

Pattern type: Persistent blink

Category: General

Indicator: Indoor unit

LEDs: YELLOW

Typical causes

Auto-drying moisture-removal sequence
Post-operation fan purge logic

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