Samsung refrigerators have several common issues. One being a defrost problem. A defrost problem means one of the auto defrost components have failed.
Samsung uses a dual evaporator system on most newer refrigerators. On some of the older Samsung refrigerators the freezer cools the refrigerator. If you have a newer Samsung refrigerator, then you most likely have a dual evaporator system. If you have a dual evaporator system, the freezer and refrigerator cool independently of each other.
The first thing you will notice if your refrigerator has a defrost issues is frost on the back wall of the refrigerator or freezer. This is always a dead give away. When the defrost heater, defrost thermostat, or control board fail the heater will never come on to defrost the coils. When one of these parts fail, the temperature inside will rise because the fan can not pull air across the coils.
If you have a good frost pattern, there will be 1/16 inch frost from top to bottom on the evaporator. The evaporator is like a radiator. The freon flows through the evaporator just like water does in a radiator. When freon is flowing through the evaporator, it is boiling. If you listen closely, you will be able to hear the refrigerant boiling it makes a hissing type sound.
The heat of the refrigerant boiling absorbs the heat from inside the refrigerator and freezer and moves it to the condenser coils. Have you ever heard someone say clean your condenser coils? The reason you want to keep them clean is the heat transfer happens there. So the freon boiling inside the evaporator draws the heat from the inside of the refrigerator and takes it to the coils on the back on Samsung refrigerators. If the condenser coils are dirty, the heat transfer will not happen. The temperature inside both the freezer and refrigerator will rise in temp.
The evaporator should have a 1/16 inch frost pattern. If it is a solid block of ice, one of the defrost components have failed. You will need to remove the back panel inside the freezer for single evaporator refrigerators. If you have a dual evaporator system, both back panels will need to be removed depending on which side is not cooling correctly.
Below is a picture of the evaporator inside a Samsung refrigerator. This evaporator has a perfect frost pattern.
If the coils are heavily frosted over, then you have a defrost issue. The fan on the back panel pulls air across these coils and moves it through out the refrigerator and or freezer.
If the coils have heavy frost on them, then you will need to make several checks with an ohm meter. The defrost heater that goes around the evaporator should have around 50k ohms. The defrost thermostat located on the right side should have continuity. If both test good, the control would be the culprit. The control is what sends voltage to the heater and thermostat.
You can force a defrost cycle ans test voltage at the heater if needed. If you want to go that far, leave a comment below or come over to the forum and I will assist you with your Samsung refrigerator troubleshooting.