297110400 Frigidaire Refrigerator Thermister is a temperature-sensing thermistor used in Frigidaire refrigeration appliances. The component is a passive temperature-dependent resistor (commonly an NTC type) that provides a variable resistance proportional to local air or surface temperature; it is indeed frequently enough referred to in service literature as a thermistor or temperature sensor. The part is small, typically mounted in a plastic housing or probe with a two- or three-conductor harness, and it interfaces directly with the appliance control board’s sensing inputs.
Inside the appliance the thermister is used to monitor temperatures at specific locations-such as the evaporator, freezer or fresh-food compartments, or air return paths-and it feeds that facts to the electronic control system. The control board measures the thermistor’s resistance (via a voltage divider or ADC input) and uses the resulting temperature data to control compressor run time,evaporator fan operation,defrost termination,damper positions and other closed-loop functions. As the thermistor provides the primary temperature feedback for those control algorithms,its placement,wiring integrity and electrical characteristics directly affect cooling performance and defrost sequencing.
This article will describe the thermister’s functional principles and typical electrical behavior, outline which Frigidaire models and locations commonly use the 297110400 sensor, identify symptoms of a failing or out-of-spec thermistor (incorrect cabinet temperatures, frequent short-cycling, persistent frost or failed defrost, or diagnostics showing an open/shorted sensor), and present practical troubleshooting and replacement considerations. Readers will find guidance on resistance checks, wiring and connector inspection, verification of sensor placement, and points to consider when selecting a replacement part to ensure correct compatibility and reliable operation.
Table of contents
- Function and Role of the Thermistor in Frigidaire Refrigeration Control Systems
- How the 297110400 Frigidaire Refrigerator Thermister Operates Within the Control and Defrost Circuits
- Common Failure Symptoms and Diagnostic Readings Indicative of a Faulty Thermistor
- Compatibility, Replacement considerations, Installation Steps and Troubleshooting Diagnostics
- Q&A
- In Retrospect
Function and role of the thermistor in Frigidaire Refrigeration Control Systems
The 297110400 Frigidaire Refrigerator Thermister is the temperature-sensing element used by the refrigerator control board to monitor compartment temperature and govern compressor, evaporator fan, and defrost functions. The sensor is a NTC device whose electrical resistance falls as temperature rises; the control board reads this resistance to infer temperature using a specific resistance‑to‑temperature curve.Replacing the thermistor with an identical part number preserves the expected curve and connector pinout so the control logic and calibration remain correct; substituting a sensor with a different resistance profile or connector can produce incorrect temperature readings even if the new sensor physically fits the mounting location.
In system operation the thermistor provides continuous analog feedback used for cycle timing, thermostat decisions, and terminating defrost. Fault behavior typically appears as temperature drift, short cycling of the compressor, failure to enter or exit defrost, or stored diagnostic codes related to open/short sensors. Technicians verify the sensor by measuring resistance at known temperatures and comparing to the expected curve; when diagnosing, also inspect harness continuity and connector seating since wiring faults mimic sensor failures. Practical service steps include confirming sensor location, recording resistance at ambient and icebox temperatures, and ensuring replacement parts match the original specification before installation.
- Common symptoms: temperature instability, continuous run, no defrost, or sensor error codes.
- Diagnostic actions: measure resistance at two temperatures, verify connector pins, compare to service chart.
- Compatibility check: match resistance curve, mounting style, and connector pinout, not just physical form.
| Item | Description |
|---|---|
| Part | 297110400 Frigidaire Refrigerator Thermister |
| Type | NTC temperature sensor (negative temperature coefficient) |
| Typical value | Approximately 10 kΩ at 25 °C (verify with service data for exact curve) |
| Function | Provides resistance-based temperature feedback to control board for cooling and defrost control |
How the 297110400 Frigidaire Refrigerator Thermister Operates Within the Control and Defrost Circuits
The 297110400 Frigidaire Refrigerator thermister is an NTC temperature sensor that provides a temperature-dependent resistance signal to the refrigerator’s control electronics and to the defrost termination logic. Installed typically at or near the evaporator coil, the part sits in a voltage-divider or ADC input on the main control board so the controller can monitor evaporator and cabinet temperatures. In the cooling cycle the control board uses the thermistor’s resistance to decide compressor run/stop and fan operation; in the defrost cycle the same input is used to detect when the evaporator has warmed sufficiently to terminate the defrost heater. Because the sensing element reports resistance rather than an on/off state, the controls can make graded decisions (for example partial run times or adaptive defrost intervals) based on the measured temperature curve.
technicians can evaluate compatibility and behavior by checking mounting, connector type, and the thermistor’s resistance-versus-temperature characteristic: resistance decreases as temperature rises for an NTC device. Common failure modes are open or shorted leads, drifted resistance, or poor thermal contact to the evaporator-each produces incorrect temperature feedback and manifests as long runs, short cycling, warm compartments, or defrost that never terminates. Practical troubleshooting steps include measuring cold and ambient resistance with a handheld multimeter, confirming secure mounting and wiring to the control board, and comparing readings to the service specification before replacing the part. Typical features and failure indicators include:
- Role in control and defrost circuits: provides analog temperature feedback for cycle timing and defrost termination.
- Behavior: NTC characteristic-resistance falls as temperature rises.
- Symptoms of failure: inconsistent cycling, warm refrigerator, frozen evaporator, or continuous defrost.
- Practical check: measure resistance and verify connector continuity and thermal placement against model specifications.
| Item | Description |
|---|---|
| Type | NTC temperature sensor (thermistor) used by Frigidaire control boards |
| Function | Feedback for compressor/fan control and defrost termination |
| Location/Compatibility | Mounted near evaporator; replacement must match connector, length, and thermal mounting for compatible Frigidaire models |
Common Failure Symptoms and Diagnostic Readings Indicative of a Faulty thermistor
The 297110400 Frigidaire Refrigerator thermister functions as the primary temperature sensing element for the refrigerator control system, converting local cabinet or evaporator temperature into a resistance signal the control board uses to regulate compressor, fan, and defrost cycles. A failing thermistor typically presents as incorrect or unstable temperature control - the unit may run continuously, short-cycle, fail to enter or terminate defrost, or allow excessive frost buildup on the evaporator. Compatibility depends on matching the thermistor’s resistance-temperature characteristic and connector to the Frigidaire control harness; replacing the sensor with a part that has a different NTC curve or connector can produce similar faults even if the connector fits physically.
Technically, diagnostic verification is done with a digital multimeter to measure resistance at stable ambient conditions and while applying controlled warming or cooling (for example, by holding the sensor between fingers to see a decrease in resistance). Key readings that indicate failure include a persistent open circuit, a near-short, or resistance that does not change when temperature is varied.Use a steady test temperature and compare behavior against the expected NTC trend-resistance should decrease as temperature increases; any deviation from that monotonic response, or intermittent continuity, indicates a faulty thermistor or wiring problem. Practical troubleshooting steps include confirming connector pins and harness continuity, comparing sensor behavior to a working unit if available, and observing control-board error codes that reference thermistor circuits.
- Open or infinite resistance: control sees no sensor input; refrigerator may run continuously or show an error.
- Near-zero resistance (short): control interprets extreme cold; compressor may not run and defrost logic can be affected.
- Resistance not changing with temperature: sensor has lost its thermistor characteristic or wiring is intermittent.
- Intermittent or noisy readings: loose connector or internal fracture causing sporadic temperature control problems.
| Item | Description |
|---|---|
| Characteristic | NTC type: resistance decreases as temperature increases; must match control board expectations. |
| Common failure indications | Open circuit, short, drifted resistance curve, or intermittent continuity producing temperature control faults. |
Compatibility, Replacement Considerations, Installation Steps and Troubleshooting Diagnostics
The 297110400 Frigidaire Refrigerator Thermister is a two‑wire NTC temperature sensor that supplies the refrigerator control board with a voltage-referenced resistance signal used to regulate compressor cycling, damper position, and defrost events.The element’s resistance falls as temperature rises; the control algorithm interprets that curve to determine when to run cooling or initiate defrost. When replacing the sensor, match the exact part number or an equivalent that duplicates the original resistance‑to‑temperature characteristic, connector style, harness length, and mounting method-differences in any of these can shift measured temperature and cause persistent overcooling, extended run times, or failed defrost cycles.
Installation and diagnostics require basic electrical measurement and careful mechanical placement: disconnect power,access the sensor location (evaporator cover or air channel),note how the sensor is secured,and replace with the new part ensuring the sensing tip occupies the same thermal environment. Verify functionality with a digital multimeter by measuring resistance at ambient and while applying a cold (ice slurry) and warm source; the resistance should decrease predictably as temperature rises. Common troubleshooting steps include checking for an open circuit, short to ground, incorrect connector pinout, or a sensor that responds too slowly due to poor thermal contact. Typical symptoms of a faulty sensor include incorrect temperature display, continuous compressor operation, or premature/failed defrost cycles-observe system behavior after replacement and confirm temperature regulation returns to expected limits.
- Compatibility checks: identical part number or matching R‑T curve, connector fit, harness length, and mounting clip/adhesive.
- Diagnostic checks: continuity, resistance change with temperature, and correct wiring to the control board.
- installation cautions: power off, avoid kinking the sensor lead, and ensure the sensing element has firm thermal contact with the air path or evaporator.
| Item | Description |
|---|---|
| Part | 297110400 Frigidaire Refrigerator Thermister - NTC two‑wire temperature sensor |
| Function | Provides resistance-based temperature feedback to the control board for cooling and defrost control |
| Key checks | Match R‑T characteristic, verify connector and wire polarity, confirm response to temperature changes |
Q&A
What is the 297110400 Frigidaire thermistor and what does it do?
The 297110400 is an OEM temperature sensor (thermistor) used on some Frigidaire refrigerators. It is a negative temperature coefficient (NTC) thermistor whose resistance changes with temperature. The refrigerator control board reads that resistance to determine compartment temperature and regulate compressor, evaporator fan and defrost cycles.
What are common symptoms of a failing thermistor?
Typical symptoms include incorrect or fluctuating temperatures in the fridge or freezer, compressor running constantly or not running at all, frequent or long defrost cycles, visible ice build-up on the evaporator, or the control board showing a temperature fault. Intermittent failures can produce erratic behavior rather than a complete loss of cooling.
How can I test the thermistor with a multimeter?
Unplug the refrigerator and disconnect the thermistor from the wiring harness. Set a digital multimeter to the ohms setting and measure resistance across the two leads. At typical room temperature (~20-25 °C) many refrigerator thermistors are around 5-50 kΩ (often about 10 kΩ), but values vary by design – consult the service manual for your model. To confirm NTC behavior, warm the sensor slightly (hair dryer) and verify the resistance decreases; cool it (ice water) and verify resistance increases. an open circuit (infinite resistance) or a short (near 0 Ω) indicates a bad sensor.
Do I need to calibrate the thermistor after replacement?
No special calibration is usually required. The control board interprets resistance directly. After replacing the thermistor, reconnect power and allow the refrigerator several hours to stabilize to verify temperatures are correct. If temperatures are still incorrect, verify wiring, connector seating, and check the control board for faults.
How do I replace the 297110400 thermistor safely?
Safety first: unplug the refrigerator. Remove shelves or panels to access the sensor (location depends on model: fresh-food compartment, freezer evaporator area, or inside the evaporator housing). Disconnect the two‑pin connector, remove any clip or screw holding the sensor, and swap the old sensor with the new 297110400. Reconnect the harness, reassemble panels, and restore power. Basic tools: screwdriver set,needle-nose pliers,and a multimeter for verification.Avoid pulling on wires and protect the evaporator fins when working near them.
Is the 297110400 thermistor compatible with all Frigidaire models?
Not necessarily. The 297110400 is an OEM part that fits specific Frigidaire/Frigidaire Gallery models. Always check the refrigerator’s model and serial number and the OEM parts list to confirm compatibility. Many aftermarket or generic thermistors will work if they have the same temperature/resistance characteristics and connector, but OEM replacement guarantees fit and specifications.
What resistance values should I expect and what do different readings mean?
Exact values vary by sensor design, but common NTC fridge thermistors are around 5-50 kΩ at room temperature (a common nominal value is ~10 kΩ at 25 °C). Key diagnostics: a reasonable finite resistance that decreases as you warm the sensor indicates a good NTC thermistor; resistance that does not change with temperature, an open circuit (OL/infinite), or a dead short (near 0 Ω) indicates failure.If you have the service manual, use the specified values for that model for accurate diagnosis.
Can a bad thermistor cause my refrigerator to display error codes or run strangely?
Yes. The control board depends on thermistor input for temperature control and defrost sequencing. A faulty thermistor can trigger error codes, cause the board to enter a default safe mode, or result in continuous compressor/fan operation or failure to cool. If you see a temperature sensor error or erratic cooling, test or replace the thermistor before replacing more expensive components like the control board or compressor.
In Retrospect
The 297110400 Frigidaire refrigerator thermistor is a small but essential sensor that monitors internal cabinet temperatures and provides real-time feedback to the appliance control board. By converting temperature changes into precise resistance signals, this thermistor helps regulate compressor and defrost cycles, maintain consistent cooling, protect stored food, and support efficient refrigerator operation.
Because a failing or out-of-spec thermistor can cause temperature swings, excessive frost, or improper cycling, accurate diagnosis is important before replacing the part. Proper diagnosis typically includes checking resistance against the manufacturer’s specifications, inspecting wiring and connectors, and following the refrigerator’s service procedures. When replacement is required, using the correct 297110400 OEM part or an equivalent specified by Frigidaire and installing it according to safety and service guidelines will restore reliable temperature control and help preserve appliance performance and energy efficiency. If there is any uncertainty about testing or installation, consult a qualified technician to ensure a safe and correct repair.
Professional Appliance Service
If your appliance requires professional diagnosis or repair, visit
Revolff Home Services
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For local appliance service information see
Dryer repair Henderson
.
Replacement parts for many appliance models can also be found at
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