The freezer fan should turn off and of course the freezer light should turn on when the freezer door is opened. With these symptoms I knew the switch was bad without even metering across the switch contacts so I just went ahead and replaced it fixing the problem. Use a screwdriver to pry the switch out and pull the connector out of the switch. Very easy for anyone to do. (Always unplug power first) This switch operates the refrigerator light and fan as well.