Samsung Air Conditioner Error Code YEL_ON_RED_FLICKER

YEL_ON_RED_FLICKER signals a discharge temperature sensor error, meaning the control board has detected either an open or short circuit in the sensor that monitors refrigerant temperature leaving the compressor. The fault is read at connector CN51, PIN#3 and PIN#4. The system may restrict operation to protect the compressor until the sensor circuit is restored to normal operation.

It is not advisable to continue running the unit with this error active. The discharge temperature sensor protects the compressor from overheating, and without a valid reading, the system cannot respond to potentially dangerous temperature conditions. Continued operation could lead to compressor damage, which is a significantly more expensive repair.

A power reset may temporarily clear the error code, but if the underlying fault in the sensor circuit at CN51 PIN#3 and PIN#4 is still present, the code will return as soon as the unit attempts to read the sensor again. A reset is useful for confirming whether the fault is intermittent, but it does not substitute for diagnosing and repairing the root cause.

A knowledgeable DIYer can start by inspecting the connector at CN51 for secure seating and checking the wiring harness for visible damage. Measuring sensor resistance with a multimeter is also within reach for someone comfortable with basic electrical testing. However, working on refrigerant-side components near the compressor and replacing control boards typically requires a certified technician.

If only the discharge temperature sensor needs replacement, repair costs typically fall in the range of $75 to $200 including parts and labor. If the wiring harness requires repair or replacement, costs may be in the $100 to $300 range. A control board replacement, if needed, can push total costs to $300 to $600 or more depending on the model and labor rates in your area.