My name is Peter. I am a retired field service technician.
You need to unplug the sensor. Place the bulb in a glass of ice water. After 10 minutes, Set you multi-meter to the lowest Ohms (Omega Symbol), touch the meter leads together you should get a reading of '1.0' or 'OL' the connector has two plugin ports, with one meter probe on the one port and the other probe in the other port, you should get a reading of 16 Ohms.
You have three sensors, one for the freezer, one for the evaporator coil and one for the freezer:
You have two defrost heaters they are part of the drain assemblies: Once again, set your meter on the lowest Ohms. Put one contact in one connector port and the other lead in the other connector port, If you get a reading of '0' or infinity the heater is bad. If it is good you should get some reading 25 to 150 Ohms.
All of these components are behind the back fresh food section and freezer wall.
I am sorry you bought a Samsung. 65% of all of my service calls were either Samsung or LG.