How to Install Freezer Temperature Sensor 297018400 in a Frigidaire Freezer

Quick answer: Unplug the Frigidaire freezer, empty the shelves that block the rear interior panel, remove the panel screws, unclip the old thermistor from its holder near the evaporator, unplug it from the harness, clip in 297018400, plug it in, refit the panel, and confirm the freezer cools to its set point.

The freezer temperature sensor, often called a thermistor, is a small sealed bead on a short lead that reads the air temperature inside the cabinet and reports it to the electronic control board. The board uses that reading to decide when the compressor runs and when it rests. When the sensor drifts or fails, a Frigidaire upright freezer may run nonstop and freeze rock hard, warm up between cycles, show a wrong temperature on the display, or flash an error code. Part 297018400 is the factory replacement for a long list of Frigidaire freezers, including GLFH17F8HWM, FFU21F5HWL and FFU17F5HWS.

On most of these units the sensor clips to a plastic holder on the interior back wall or near the evaporator, behind the rear cover panel inside the compartment, and its lead plugs into the main harness. The repair is easy in principle; the awkward parts are working in a cold cabinet, coaxing an old plastic panel loose without cracking it, and keeping food from thawing while you work. Allow 20 to 45 minutes and have coolers ready before you unplug.

See part details and every compatible model: 297018400

⚠️ Safety First
  • Unplug the freezer before removing any interior panel; the fan and defrost circuit can start unexpectedly.
  • Move perishable food to coolers first; a full freezer keeps its contents frozen for the length of this job if the door stays shut.
  • Wear gloves. Cold aluminum fins and stamped panel edges cut easily.
  • Do not pry against the evaporator tubing; a nicked tube means a sealed-system repair.
  • If the panel is frozen in place, let it thaw for a few minutes rather than forcing it.

Tools and Parts You Need

  • Phillips or quarter-inch nut driver for the rear panel screws
  • Small flat screwdriver or plastic trim tool to release the sensor clip
  • Multimeter to check the old sensor before ordering
  • Flashlight
  • Work gloves, ideally insulated for the cold
  • Coolers or insulated bags to hold food during the repair
  • Towel for melt water

Step-by-Step Installation

  1. Unplug and empty Pull the plug, then move the food to coolers and remove the shelves or baskets that cover the rear interior panel.
  2. Remove the rear panel Back out the screws holding the cover on the back wall. Ease the panel forward; ice may hold it, so wiggle gently and wait if it resists.
  3. Locate the sensor Find the small bead sensor in its plastic clip on the back wall or beside the evaporator. Its lead runs a short distance to a connector on the harness.
  4. Unplug the old thermistor Follow the lead to the plug, press the latch, and separate it. Photograph the routing so the new lead can follow the same path away from the fan and the fins.
  5. Release the clip Slide the sensor out of its holder. On some models the holder itself unclips from the wall; on others the sensor simply slips free. Avoid breaking the brittle plastic.
  6. Install 297018400 Seat the new sensor in the holder with the bead in the same position as the old one, then route the lead along the original path and plug it in until it clicks.
  7. Refit the panel Replace the rear cover and its screws, checking that no wire is pinched between the panel and the wall. Reinstall the shelves and baskets.
  8. Test the freezer Plug the freezer in, load the food, and let it run. Within an hour or two the display or a thermometer should show it pulling down toward the set point and the compressor should cycle off.

Fit Checks Before You Call the Job Done

  • Bead size and lead length match the old sensor so it reaches the holder without strain
  • Connector shape matches the harness plug and latches
  • Sensor seats in the existing clip without tape or improvised holders
  • Freezer cycles off once it reaches temperature rather than running constantly
  • Model number on the door label, such as FFU21F5HWL or GLFH17F8HWM, is listed for 297018400

Common Mistakes to Avoid

Diagnosing by guess A freezer that runs constantly can also have a bad door gasket, a failed evaporator fan, or a frost-choked coil. Measure the old sensor and check for frost buildup before replacing it.

Cracking the rear panel Cold plastic is brittle. Warm it slightly and release all screws, including hidden ones under a plug or label, before pulling.

Mounting the bead in the wrong spot The control expects the sensor at the factory location. A bead resting against the evaporator or the wall reads far off and causes short or endless cycles.

Pinching the lead A wire trapped under the panel chafes and eventually opens. Route it along the original path and check before tightening.

Overloading a warm cabinet Let the freezer cool before packing in a large amount of unfrozen food; the extended run can look like the fault has returned.

Troubleshooting After Installation

Freezer still runs nonstop Confirm the plug is latched and the bead is in its holder. Then inspect the evaporator for heavy frost and the door gasket for gaps; either can mask a good sensor.

Error code persists Unplug the unit for a few minutes to reset the control, then power up. If the code returns, check the harness side of the connector for a pushed-back pin.

Temperature display reads wildly wrong The sensor may be touching a cold surface or the lead may be damaged. Reposition it in the clip and inspect for cuts.

Freezer will not start at all This is not a sensor symptom. Check the outlet, the power cord, and the control board before pulling the panel again.

Care Tips After the Repair

  • Keep the door seal clean and close the door firmly; frost from a leaking gasket is the most common reason a good sensor looks bad.
  • Do not stack food against the rear panel; the sensor needs air moving past it to read correctly.
  • If the freezer is manual defrost, defrost it before ice reaches the rear cover.
  • Check the displayed temperature against a freezer thermometer every few months.

Compatible Models (Sample)

This part is listed for 254 Frigidaire models in our fitment data. Always confirm your exact model number on the appliance's rating plate.

Repair Difficulty and Time

Difficulty: Easy. Typical time: 20 to 45 minutes.

Frequently Asked Questions

How do I know the sensor is bad before buying 297018400?

Unplug the freezer, disconnect the sensor, and measure it. A reading that is open, shorted, or that does not change when you warm the bead in your hand points to a failed sensor.

Where exactly is the sensor on a Frigidaire upright?

On most models it clips to the interior back wall or the evaporator cover area behind the rear panel. Some chest models mount it on a side wall instead.

Will my food thaw during the repair?

Not if you keep it in coolers and work steadily. The freezer itself stays cold for a good while with the door shut.

Does this part fit Kenmore freezers too?

Yes, it is listed for a number of Kenmore units built on the same platform, such as 25328052806. Confirm your full model number first.

Final Checklist

  • Freezer unplugged, food moved to coolers
  • Shelves and rear interior panel removed without damage
  • Old thermistor unplugged and unclipped, routing photographed
  • 297018400 seated in the holder in the factory position
  • Connector latched, lead routed clear of the fan
  • Panel and shelves reinstalled, no pinched wire
  • Freezer reaches set point and cycles off

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