second thermister location

Having defrost issues. I’ve replaced the defrost heater(it was visibly fried), but still not defrosting. I want to change the thermostat and thermisters, but the diagram shows two thermisters. I can easily see the one near the top of the coil, but I can’t locate the one that shows near the lower portion of the diagram(part #241). Thank You. (hoping it’s not the board)