Testing A Refrigerator Thermistor On A GE Refrigerator

This page is for testing a refrigerator thermistor that is on a GE electronic refrigerator made after 2002 only. Including top-freezers, bottom-freezers, and side-by-side models.



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Note that all thermistors on these refrigerators are the same. This means that they will have the same part number no matter what part of the refrigerator it is located. Also they are sometimes called a temperature sensor.



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These are a few other pages that will help you with your GE refrigerator repair.



GE Refrigerator Not Cooling


GE Refrigerator Not Running


GE Refrigerator Fan Motor


GE Refrigerator Too Cold


When a refrigerator thermistor goes bad the refrigerator can become a lot less efficient, stop cooling completely or not defrost properly, depending on which thermistor is bad. This page will guide you on how to check these thermistors when you suspect they are bad.

Checking A GE Refrigerator Thermistor From The Main Board

You can check the refrigerator thermistor directly from the main board or you can check them by cutting them out. Checking thermistors from the main board is the best way, but the only thing is that it is a little complicated. If it is too complicated for you there are directions on how to test a thermistor by cutting it out at the bottom of this page.

The main thing is that if the refrigerator were cooling properly, you wouldn’t be testing the thermistors. So you don’t know what the temperature of the thermistor is. Placing the refrigerator thermistor in a cup of ice water easily solves this problem. First, locate the thermistor (see pictures below), once you locate the thermistor, place it into a cup of ice water (more ice than water). You should be able to sit the cup on a shelf and place the thermistor in the cup (make sure it is in the ice good). Then wait for at least five minutes for the temperature of the thermistor to reach 32 degrees. If you do not test the refrigerator thermistor with it in a cup of water you will not know what the ohm reading should be. With the thermistor in a cup of water, the ohm reading should be around 16.6 K ohms or 16,600 ohms +/-5%.

Next unplug the refrigerator and locate the main board on the back of the refrigerator. There is a plug marked J1 on the board and that is where the thermistors are connected. There are 9 pins on that J1 plug. The first 5 are the ones for the thermistors, one for each of the four thermistors and one common (connects to each thermostor). Note that not all refrigerators will have four thermistors, in fact most of them will only have three.

Evaporator Thermistor

The evaporator thermistor is the one attached to the top of the evaporator coils in the freezer (see picture below).

Evaporator thermistor location

The evaporator thermistor controls the defrost cycle, so if it is bad the refrigerator will not defrost and the coils will look like this.

Coils iced up

If you perform this test before you melt all the ice there is no need to place the thermistor in the cup of water because it is already wrapped in ice and it should be around 32 degrees and ready for testing. Disconnect the J1 plug and start the test. On the plug there are 9 pins. Place one lead of the ohmmeter on the fifth (counting from left to right) wire and the other on the fourth wire and it should read around 16.6 K ohms or 16,600 ohms +/-5%. Note that testing is done on the plug not the board and the plug must be disconnected so that you don’t get a false reading through the board.

If the coils look like and the thermistors test ok see this page GE Refrigerator Not Cooling

Freezer and Fresh Food Thermistors

The freezer thermistor is located at the bottom of the freezer near the drain pan (see picture below). The fresh food thermistors are in the fresh food section and depending on the model they will be in different places. Some have the thermistor at the top and it is connected to the damper. On other models they are behind a little griddle on the sidewall of the refrigerator (see picture below). The freezer thermistor, along with the fresh food thermistors, will send signals to the main board so that it can determine when to turn the compressor off/on, speed up/slow down/cut off the fans or open/close the damper. If one of the thermistors is bad the refrigerator will not cool correctly.

If the refrigerator is not cooling properly and you suspect you have a thermistor problem, it is best to test both the freezer thermistor and both of the fresh food thermistors. Note that on most of these refrigerators there is only one thermistor in the fresh food section.

Freezer Thermistor

We will start with the freezer thermistors. Disconnect the J1 plug and start the test. On the plug there are 9 pins. Place one lead of the ohmmeter on the fifth (counting from left to right) wire and the other on the third wire and it should read around 16.6 K ohms or 16,600 ohms +/-5%. Note that testing is done on the plug not the board and the plug must be disconnected so that you don’t get a false reading through the board.

Note that you will only get a 16.3 ohm reading if you have placed the thermistor in the cup of ice water as previously mention at the top of this page.

Freezer thermistor location

Fresh Food Thermistors



Next lets test the fresh food thermistors. Disconnect the J1 plug and start the test. On the plug there are 9 pins. Place one lead of the ohmmeter on the fifth (counting from left to right) wire and the other on the first and the second wire (note that you may not have a second wire and if not, you only have one fresh food thermistor). Both should read around 16.6 K ohms or 16,600 ohms +/-5%. Note that testing is done on the plug not the board and the plug must be disconnected so that you don’t get a false reading through the board.

Note that you will only get a 16.3 ohm reading if you have placed the thermistor in the cup of ice water as previously mention at the top of this page.

Fresh Foo thermistor location

A Simpler Way To Check A Refrigerator Thermistor

If this all confuses you there is a simpler way to check a refrigerator thermistor. The problem with this way is you have to cut the wires and then if the thermistor isn’t bad you have to reinstall the thermistor. On some of these thermistors once you cut the wires you can’t reinstall it easily due to the short wires.

Remove the thermistor and place it in a cup with ice and a small amount of water for at least five minutes. This should bring the thermistor to 32 degrees. Using your ohmmeter, check resistance across the thermistor with it still in the ice water. It should read around 16.6 K ohms or 16,600 ohms +/-5%. If you don’t own an ohmmeter or are unsure how to properly use it, replace the thermistors if you suspect they are bad.

If your refrigerator was made before 2005, this picture will help you identify faulty thermistors (thermistors that came from the factory with a high failure rate). Refrigerators made after 2005 may have thermistors that look like the one that says faulty but is ok. Because they start back using a thermistor that looks like the faulty one but it is not faulty.

Alternative Method For Testing A Refrigerator Thermistor

On this page I talk about testing thermisotors by placing it in a cup of ice water to bring the temperature of the thermistor to 32 degrees (F). This is the way I prefer testing thermistors and it is the way I recommend testing because it gives you a very controlled test. However some people don’t like this method. Here I give you an alternative method to testing thermisotrs.

Get an accurate temperature reading close to the thermistor you will be testing. Then at the main board test ohms across the thermistor using the pins described above. Then look at the chart below to compare what ohm reading should be according to the temperature at the thermistor. Note that it is important to take ther temperature as close to the thermistor you wish to test as possible.

Temperature
(F)
Temperature
(C)
Resistance
-13 -25 65K Ohms
-4 -20 48.4K Ohms
5 -15 36.4K Ohms
14 -10 27.6K Ohms
23 -5 21K Ohms
32016.3K Ohms
41512.7K Ohms
501010K Ohms
59157.8K Ohms
68 206.2K Ohms
77255K Ohms
86304K Ohms
9535 3.2K Ohms
104402.6K Ohms

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