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ZFSB23DRHSS Freezer cold, fridge not so much


Premium Member
Jul 24, 2016
Model Number
6-10 years
A friend has the above model, side-by-side. Freezer is set at 0 degrees, readout on frig is 0-1 degrees, and confirmed by thermometer. Frig is set at 36, readout is 44-45 (pretty consistently), and thermometer reads 38-50 - obviously varying widely. Cold air blows from the vents in the back of the frig. Can hear fan(s) running much of the time.

Removed freezer coil cover and am including a photo. Manually defrosted coils and reassembled. In about two hours frig was down to 34 (by thermometer); readout was still 44.

I'm guessing thermistor might be bad (readout inaccurate, fan running too much). How many thermistors are there that should be tested and where are they? How do I test them? Anything on the computer board I should be checking? If so, what and where is it?

Thanks for your help!!

Just about everything can be checked at the main board. The thermistors can be checked in the J1 connector. J1-5 is thermistor common. Measure the resistance of each thermistor then check it against the temperature in the chart. If it's within a few ohms it's probably OK. If the thermistor is open, shorted, or out of range, Take the thermistor and place it in a small glass of crushed ice and just enough water to cover it. Wait a few minutes then measure the resistance. At 32 *F the thermistor should have 16.3KΩ. Make sure your meter is on the correct setting. Note the thermistors are measured in KΩ. K=1000 - 16.3KΩ= 16,300Ω
011 GE Thermistor Chart.jpeg
Thanks for the quick reply. Should be able to check this in the next couple days and get back to you.
1) 15.4k (34*)
2) 12.2k (41*)
3) 33.3k (7*)
4) 55k (-8*)

#4 seems to be way off but your notes say that's not always used. I'm not sure where to find the evap thermistor to test it. Can you give guidance? Should I test all the others? They seem to be in the ballpark of the actual temperature.
Put the frig thermistor in ice water - measured 14.7k. Is that “close enough” or do I replace it? That’s #2 above.
Replace it. I place the thermistor in a shot glass filled with crushed ice and just enough water to cover it. After one minute or so, the thermistor will be about 32*F. At 32*F the thermistor should show 16.3KΩ. The evaporator thermistor is located on the top of the freezer evaporator in a clip:
Thermistor WR55X10025
Replaced thermistor's #2 and #4. Frig now reads 42* even though it's set to 36. Any other tests we can do? Next step?
6 degrees can be the difference in temperature between the top and bottom of the fresh food compartment. What are you using to measure the temperature and where are you measuring it at? Put your thermometer as close to the FF thermistor as possible.
We're using a dial thermometer.

While the frig may be a little cooler it's not too stable. I was just visiting today and the frig was about 40. Two hours later I looked and it was 32. Everytime I checked the compressor was running.

Thoughts on what to do next?
Your temps are in the ballpark. Those thermometers have a +/- of several degrees. Did you try cleaning the condensor coils under the machine?
I did vacuum what I could reach from the back but the coils are circular so it's hard to get all around. Perhaps we need to get a brush or attachment of some sort.
Try switching the hose on the vacuum and try blowing it out. If you got most of it, that should be good enough.
I'd say we might have gotten access to 1/3 of the coils. I have a friend with a brush and we'll try that. The gunk on the coils was very sticky - I doubt blowing it off would work but that's something to try.

I'll keep you posted.
Brushed the coils and used compressed air - cleaned them up well. Unfortunately, no real improvement. While the freezer is close to zero degrees, the frig is typically 40-45.

Next steps? I'm considering a dive into the back panel of the frig side but that looks involved. I'm wondering if the air vent is obstructed or stuck only partially open. While air is blowing in, perhaps it's not enough.
Rick had to go out of town for a family issue.

Look at my post#2 here: PSC25MSWASS Temp To Warm, Wont Cool

See if that fan is running in my post where I explain about it, your model uses that exact same fan assembly as in post#2.

Here it is:
GE WR17X13035 Qc Fan & Harness Asm

Also see if your refrigerator evaporator coil has a ice ball on it, there is a ice ball kit to resolve that problem if so.

This model has 5 thermistors.Change them all.There is one in the fresh food section in a block on the backside evaporator that maybe the problem, but being this thermistor are cheap I would change them all.The one in the block GE recommends that you don't remove the block to change the thermistor as you will never secure it as tight.Also look at that fan motor Jake pointed you to. Here is some information that may help you.


  • Tech-Tips-GE-Thermistor.pdf
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  • 31-51518 GE ZFSB23DRHSS Mini Manual.pdf
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  • 31-9153 GE Profile Side by Side Refrigerator Service Manual.pdf
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Thanks Bigbuck!

Thanks, folks. This work is definitely going to be worth another beer. ;-)
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