Temperature sensor of evaporator

Inconsistent ice thickness and failed harvest cycles frequently trace to an evaporator temperature sensor that no longer accurately reports plate temperature to the control board. This 1851700500 temperature sensor determines the precise moment when ice has reached optimal thickness, triggering the harvest sequence before over-freezing causes bridging or slab formation. When this thermistor provides erratic readings, youll observe symptoms including thin or incomplete cubes, ice bridging across the grid, and extended freeze cycles that never terminate properly. Technicians diagnose sensor issues by measuring resistance across the probe leads while comparing against the manufacturers temperature-resistance chart. The sensor should read approximately 10,000 ohms at 77°F, with resistance increasing as temperature drops. A sensor detached from the evaporator plate reads air temperature rather than plate temperature, causing premature harvest initiation and thin ice production. Ice accumulation around the probe tip insulates the sensor from the plate, creating similar symptoms. Installing this replacement evaporator temperature sensor restores the precise temperature feedback that controls freeze cycle duration. The control board uses this data to initiate hot gas defrost at the optimal ice thickness, ensuring clean cube release without excessive energy consumption. For field service professionals, this component resolves thin ice, ice not dropping, and long freeze cycles complaints that indicate temperature sensing failures rather than refrigerant or mechanical issues.