So how does a thermistor begin malfunctioning if indeed it is?
The answer begins with what a thermistor does.
This contraption is essentially a sensor, keeping tabs on room temperatures within your unit.
When temperatures change, be it descending or increasing, the thermistor sends signals to the control board.
For a Frigidaire refrigerator thermistor test to be carried out, one requires meters used mainly by professionals.
However, there are other basic methods one can apply, like monitoring the fridge, to check the Frigidaire thermistor.
Although this is not an easy part to understand in terms of its workings, the outcome is pretty visible.
Either the signals sent to the control board mirror what is happening inside the fridge, or they do not.
Symptoms of Bad Frigidaire Refrigerator Thermistor
The signs and symptoms that indeed your Frigidaire refrigerator thermistor has a problem begin with fluctuating temperatures.
1. When the thermistor sends the wrong signals to the control board, your fridge will change temperature settings erratically.
It means even if the fridge is at optimal temperatures, it may begin to cool further, albeit the settings or temperatures haven’t changed.
2. If the thermistor is faulty, food and beverages will remain warm instead of cooling.
This will continue even after one changes the temperature settings manually.
During the day, temperatures might not only drop, but they might also rise and fall abruptly.
3. Other symptoms of a faulty thermistor involve frost.
The evaporator fan needs to condense and remain frost-free.
If the thermistor is misbehaving, the evaporator will have ice buildup which will also be evident elsewhere within the fridge.
4. As the owner of a modern Frigidaire fridge, the unit is likely to boast a display panel.
If the temperature displayed is inaccurate, the thermistor is likely to be the problem.
These all require a Frigidaire refrigerator thermistor test as soon as possible.
5. The most obvious symptoms of a faulty thermistor are a warm fridge with no signs of cooling down.
When the frost is turning to water even with lowered temperatures, the thermistor has a problem.
Frigidaire Refrigerator Thermistor Test
Because this is indeed an electrical appliance, all tests should be carried out when the unit is off.
Unplugging wires and running fingers through harnesses should be done with gloves on, and no electricity running through it.
When the Frigidaire refrigerator thermistor test requires expertise, hire an expert.
They can apply their skills, along with the instructions found on tech sheets inside the fridge.
Reveal the wiring and thermistor
Open or bring down the control board, depending on your unit, to reveal the wiring and the thermistor.
Examine the wire harness to ensure power is running through the wires.
If the harness seems okay, move to a Frigidaire refrigerator thermistor test using a multimeter.
Check readings
Remove the thermistor and connect the corresponding wires.
These might not be color-coded but connecting them should be a breeze.
For optimal readings of any thermistor, most fridges have a tech meter placed within the refrigerator.
Check the readings and compare them with advised measurements on the chart.
Any reading that is +/- ten percent warrants a replacement of the thermistor.
Compare readings
When you test the thermistor wiring, connect the meter wires to the black and grey, and another to the red wire.
If the readings are not similar to the tests tried in steps 2 and 3, the wiring harness and thermistor wires need to be replaced.
For some models, a room temperature reading of 72 degrees Fahrenheit warrants 10 ohms readings.
When you test the same with a cup of ice, under room temperature, the readings should be around 27,000 ohms, at 32 degrees Fahrenheit.
These readings are essential when stepping into step four below.
Test the thermistor at room temperatures
Plug the thermistor back into its harness and remove the 12-pin connectors.
Connect it directly and the temperatures should mirror what outside temperatures read.
When testing the thermistor at room temperatures, with a cup of ice water, for example, readings should be similar inside the fridge.
These steps are not easy to apply and might require a helping hand.
Be sure to seek the help of a professional who can carry out the steps seamlessly.
It also helps avoid further damage to the unit.
Check other parts of fridge for temperature fluctuation
Other parts that might be causing these fluctuations in temperature involve the control board.
After performing the above steps and wiring harnesses seem okay, chances are the thermistor is okay.
When evaporator fans or compressors are malfunctioning, the same symptoms listed above will be witnessed.
It is thus important not to rush to replace the thermistor but to check these parts of the fridge first.
Check refrigerator tech sheet and instructions
Aside from testing the thermistor itself, there are other methods applied to eliminate the chances of the thermistor being faulty.
Every fridge has a tech sheet. Using this sheet and instructions, turn the Frigidaire fridge to test mode.
This allows you to check if the control board or compressor has issues.
If the tests prove there are in fact problems with the control board, you can outrightly dismiss thermistor issues.
How to Bypass Frigidaire Refrigerator Thermistor?
If your fridge is not cooling, and in this case is getting warmer, you might need to bypass the thermistor or thermostat.
This requires expertise to be carried out efficiently.
It also requires that you turn the fridge off or unplug it first.
1. The first step is to set the temperature to the coldest setting.
Proceed to unplug the unit and plug in an external thermostat.
This can also be used to test if the thermostat or thermistor is working properly.
Bypassing it entirely requires other procedures.
2. Additionally, performing a bypass only allows one section of the fridge to work optimally.
It means the freezer section of the side-by-side refrigerator will not maintain optimal freezing temperatures.
3. Bypassing the thermostat requires jumping cooling and heating functions.
This is a step better left for professionals.
It involves connecting red, green, and blue yellow precisely and with keenness to avoid mishaps like short circuits and such.
The bypass covers the condenser motor and other parts linked to the thermistor and improves or maintains optimal performance inside the fridge.
Better and more professional methods are available using a local electrician.
4. An easier method involves alligator clips applied to the red and yellow wires.
These might vary according to the model, and this step needs to be applied by a professional.
The idea is to remove the power source from the thermistor and apply it directly to the condenser for instance.
Frigidaire Refrigerator Thermistor Replacement
A Frigidaire refrigerator thermistor replacement should never be carried out amateurishly.
This step involves wires and of course electricity.
It is ill-advised to apply any techniques herein alone or without expert supervision.
Here are the steps that should be taken for proper Frigidaire refrigerator thermistor replacement.
1.Unplug the unit from its power source. Before unplugging any wires, including harnesses and the thermistor to be replaced, no power should be running through the fridge.
2. Remove shelves and especially lower compartments usually associated with vegetable storage.
Remove glass inserts or shelves that might obstruct repairs or be broken during replacements.
3. After removing all shelves and especially glass shelves, remove the housing or door covering the rear duct.
This holds all the harnesses and wiring necessary to replace the thermistor.
4. The thermistor is placed immediately on the sides of the duct after removing the cover.
It can be located by glancing through the left or right sides after screwing off the main duct cover.
This usually is in the form of a wire and small harness.
5. Place the new thermistor in place, remembering to ensure the refrigerator is turned off.
This process of replacing with a new one should take less than 3 minutes.
6. Once the new thermistor is in place, return it and the wiring back to the sides of the duct. Once the thermistor is properly secured, return the cover to its place.
Be sure to screw it back in firmly to avoid moisture and or water trickling in and damaging the thermistor in the future.
7. Place all shelves and glass fittings back into place slowly, but only after the covers have secured the duct and wiring.
Once this is done, plug your fridge back into the power source and observe its performance over 24 hours.
If the French door fridge has a lower freezer section, it might also require replacing the thermistor.
This requires extra tools to remove the drawer from its tracks.
Once the drawer is out, the thermistor is easily located above the freezer room, underneath its housing.
Remove it and replace it accordingly, then start the fridge while monitoring the changes in temperatures.
Recommendations
Because all fridges are different it is important to pay attention to user manuals.
These offer a guide on proper usage of the fridge and minor troubleshooting.
However, the tech sheet provides a guide to temperature readings, tests, and other factors important when replacing such parts as the thermistor.
The Frigidaire refrigerator thermistor test might reveal some heavy work that needs to be done, requiring expertise.
Be sure to consult and hire professionals only.
References:
https://www.searspartsdirect.com/diy/article/diagnosing-refrigerator-thermistor-problems-video
https://allthumbsdiy.com/appliances/how-to-test-and-replace-thermistor-temperature-sensors