Genuine Daikin 1719415 Thermistor Set is the set of temperature sensors that give the unit the readings it uses to run correctly through the cycle. When one starts to fail, the unit may struggle to hold output, run hot or cold, or stop and start at odd times. A genuine set reads temperature the way your Daikin expects, keeping the unit accurate — where a non-genuine part can read off and leave it running incorrectly.