How do I replace the Thermistor?

by Triple G
(Virginia Beach, VA)

I've read all your information about my GE gss25wgmd. I suspect the thermistor.

The coils continue to get covered with frost in less than a week. My defroster heater works (tested by jumping the wires on the mother board). I tested the resistance across a thermistor and it only varied from 2.2 KOhm (dry) to about 8 KOhm (cold in ice water).

But I can't figure out how I will replace it when a new thermistor arrives. Will it come with a whole new harness? Also, the wires for the lower thermistor route into the side wall and I can't see where to disconnect it to test it.

Thank you for this great service.

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Hi Triple G,

I have been meaning to write a section on the correct way to install a thermistor I just haven’t got around to it so I am glad you asked.

You will have to splice the wires. The best way to do this is with a bell connector, which is just a one-ended squeeze connector. You will have to have a tool to correctly squeeze the connector to make a good connection. Skin the wires about a ¼ of an inch or so and twist the wires together then fill the bell connector with silicone RTV. Push the wires into the connector and squeeze the connector with the tool. The silicone assures moisture will not get to the connection.

Note that if you do not have a tool you can use wire nuts but they aren’t as good. Also if you use wires nuts still fill them with silicone.

Thank you,

Comments for How do I replace the Thermistor?

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Is there a way to test the timer on the Mother Board?
by: Triple G

Thank you for the quick response.

Is there a way to see if the Mother Board is getting the correct input and sending the signal to turn on the defroster? I've read that the timer for this model is on the MB, is there a way to see if the timer is the problem?

Thank you,
Triple G

by: Shawn/Admin

Not with out special equipment but I believe the thermistor is the problem. If the thermistor is reading 2.2 K that means that thermistor ?thinks? the temperture is 113 degrees (F) so unless you checked the thermistor outside on a very hot day the thermistor is bad. Also 8 K means that the thermistor ?thinks? that the temperture in the ice water was about 60 degrees (F) or so and it should have been around 32 degrees.

The board doesn?t fail in this regard often but yes it can cause this problem, if you replace the thermistors and it doesn?t work replace the board. I don?t like to say just throw parts at it but we know from the ohms readings that the thermistor is bad.

Also they don?t give you a lot of wire to work with on that bottom thermistor so make sure you cut the wires right behind the old thermistor so that you know you have enough wire.

Thermistor install
by: Anonymous

When splicing in the new thermistor does it matter which wire goes where? Are they marked or color coded?

by: Shawn/admin

It doesn't matter.

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