those readings actually sound good. the thermistor regulates the operating temperature. if the unit gets to hot the thermal fuse will blow, leaving you with no heat. the thermostat is a high limit thermostat, so in the event that the heater housing overheats it will open and cut power to the heater and start over. it works in conjunction with the high limit, so if the temp in the heater gets out of hand it will blow and you get no heat. when you measure the dryer temperature you do it at the exhaust vent. it should measure around 160 on high. you may also want to ensure that the heater coil did not warp and ground to the heater housing. most likely though, is that the unit sat for a while and lint/pet hair/dander settled on the element an burned off. make sure there is no lint built up in the unit.