This video demonstrates how to test a two terminal switch on a refrigerator. The door switch is the most commonly replaced part for a refrigerator when the light isn’t working.
Other more commonly replaced parts for a refrigerator that won’t dispense water or ice are:
Water inlet valve Dispenser control board Water filter
All of the information provided in this part testing video is applicable to the following brands: Amana, Frigidaire, GE, Kenmore, KitchenAid, LG, Maytag, Samsung, Whirlpool