Maytag Model #MBB2256GES

defrost heater is not engaging, I took out the switch (range 45-30) froze it in my freezer to 5 degrees below zero and it made continuity and opened when I put my hand around it. Could not tell when it made contact or if there was a problem with the switch itself. I checked the derost coil and it made continuity about 37 ohms. The fanworks as does the compressor. I still suspect the switch but with no diagram cannot ruile out other interlocks or controls.