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Error code reference

Samsung Air Conditioner Error Code YEL_ON_GRN_ON

Heatsink temperature trip

Samsung codesSamsung air conditioner codes

Heatsink temperature trip

First step from the service manual

Check outdoor unit ventilation, fan motor, fan motor drive circuit

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

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What YEL_ON_GRN_ON means on a Samsung air conditioner

The YEL_ON_GRN_ON error code on Samsung air conditioners indicates a heatsink temperature trip. This fault occurs when the heatsink attached to the inverter's power module or IPM (Intelligent Power Module) in the outdoor unit exceeds its safe operating temperature threshold. The heatsink is a critical thermal management component that dissipates heat generated by the inverter drive circuitry during compressor speed control. When this temperature trips, the system shuts down to prevent permanent damage to the power electronics.

The most common causes are related to inadequate heat dissipation in the outdoor unit. Blocked or restricted airflow around the outdoor unit prevents the heatsink from cooling properly. The outdoor fan motor and its drive circuit are directly responsible for moving air across the heatsink fins, so any failure in the fan motor, capacitor, or drive circuit can cause heat to accumulate rapidly. Ambient temperature extremes, debris clogging the condenser coil or heatsink fins, and inadequate clearance around the outdoor unit all contribute to thermal overload conditions.

Diagnosis should begin with a visual inspection of the outdoor unit for blocked airflow, followed by verifying that the outdoor fan is spinning at the correct speed during operation. The fan motor drive circuit should be checked for proper output voltage and signal integrity. If the fan and airflow are confirmed normal, the heatsink itself, its thermal paste or pad, and the IPM board should be inspected for signs of overheating, physical damage, or degraded thermal interface material.

Source: manufacturer service documentation.

Common causes of YEL_ON_GRN_ON

  1. 01

    Blocked outdoor unit airflow

    Wiring / connection

    Debris, vegetation, or nearby structures restricting airflow around the outdoor unit prevent the heatsink from dissipating heat. Inspect all sides of the outdoor unit for obstructions and ensure minimum clearance requirements are met.

  2. 02

    Outdoor fan motor failure

    Part replacement

    A failed or underperforming outdoor fan motor reduces airflow across the heatsink, causing rapid heat buildup. Check that the fan spins freely, runs at the correct speed, and draws appropriate current during operation.

  3. 03

    Fan motor drive circuit fault

    Part replacement

    A fault in the fan motor drive circuit can cause the fan to run at reduced speed or not at all, even if the motor itself is functional. Inspect the drive circuit board for burnt components, failed capacitors, or incorrect output signals.

  4. 04

    Dirty or clogged heatsink fins

    Wiring / connection

    Accumulated dust and debris on the heatsink fins insulate them and dramatically reduce their ability to release heat. Clean the fins carefully with compressed air or a soft brush as part of the diagnosis.

  5. 05

    Degraded thermal interface material

    Part replacement

    Over time, the thermal paste or thermal pad between the IPM power module and the heatsink can dry out or degrade, increasing thermal resistance. This requires disassembly of the outdoor control board assembly to inspect and replace.

See the test procedure for each cause

Frequently asked questions about YEL_ON_GRN_ON

What does YEL_ON_GRN_ON mean on a Samsung air_conditioner?
YEL_ON_GRN_ON indicates a heatsink temperature trip in the outdoor unit. The heatsink is a metal component that cools the inverter power module controlling the compressor. When this heatsink gets too hot, the system shuts down automatically to protect the electronics from permanent damage. The yellow and green LED indicators on the outdoor unit control board illuminate together to signal this specific fault condition.
Can I fix the YEL_ON_GRN_ON error myself?
Some causes of this error are accessible to knowledgeable DIYers. Clearing debris from around the outdoor unit, cleaning clogged heatsink fins, and verifying that the outdoor fan is spinning are reasonable first steps. However, diagnosing and repairing the fan motor drive circuit, replacing the fan motor, or servicing the IPM board involves working with high-voltage components and should be performed by a qualified technician.
Is the YEL_ON_GRN_ON error on a Samsung air conditioner dangerous?
The error itself represents a safety protection feature, not an immediate hazard. The system shuts down to prevent damage to the inverter power module, which could otherwise fail in a more serious way if overheating continued. You should not attempt to defeat or bypass this protection. Leave the unit off and diagnose the root cause before restarting.
Will resetting the unit clear the YEL_ON_GRN_ON error?
A power reset may temporarily clear the fault and allow the unit to restart, but the error will return if the underlying cause is not resolved. If the heatsink or airflow issue persists, the unit will trip again, often faster on subsequent attempts as residual heat remains. A reset without diagnosis and repair is not a lasting solution.
How much does it cost to repair the YEL_ON_GRN_ON error on a Samsung air conditioner?
Repair costs vary significantly depending on the root cause. Cleaning and airflow corrections may cost little to nothing beyond a service call fee, which typically ranges from $75 to $150. Fan motor replacement generally falls in the $200 to $450 range including parts and labor. Control board or IPM repairs can range from $300 to $700 or more depending on parts availability and the extent of the damage.

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