The refrigerator light has started operating intermittently. No physical switch is visible. I am told it is a magnetic device of some kind and I need a service call. Recently, with the door open and the light not on, I moved a tall, opaque plastic bottle on the top shelf about an inch to the left and the light went on. Opening and shutting the door, the light operated properly. Seems like some kind of radio or light signal was being blocked by that bottle.

How does the refrigerator light switch function? (No physical switch visible) Is there a explanation for this phenomenon that does not go into the supernatural? Thanks for any thoughts.