Brand: GE Model Number: GSH25JSDB Main Symptom: Inaccurate main board temp readings on thermistors What happens & when:
Hi, I will try to be brief. The defroster heater in the fridge burnt out in April 2026 which I replaced successfully. There was also a burnt area on the main board so I also replaced the main board as well and the fridge has run well for the last 3 months with no issues. However yesterday the fridge was warming up and my daughter noticed the ice cream had melted. After checking many things including the stater relay, capacitor, ohms on compressor, the only I could find is that the main board was not reading the thermistors correctly. The display on the front of the fridge would indicate a temp of 12 F but the actual temp was 56 F in the fridge section. The freezer section showed 9 F on front display but actual temp was 38 F (based on Fluke thermocouple measurement). When I unplugged the fridge and let sit for several minutes and then plugged back in the fridge temp readings were accurate and the compressor started. I tried inspecting the main board and re-seating connectors but so far it seems random where the main board will stop reading correct temps on the thermistors. Not sure what is going on, perhaps its a defective main board or some intermittent wiring issues. Any suggestions welcome, I initially suspected bad thermistors but that doesn’t appear to be the case since the temp readings are correct once the fridge is unplugged and plugged back in again.
Also I am trying to teach my son how to fix things as we go and do multimeter measurements to help diagnose the problem. My hope is we fix this together.
Based on everything you’ve described, I actually think you’ve done an excellent job narrowing this down.
The fact that both thermistor readings become wildly inaccurate at the same time, then immediately return to normal after cycling power, makes it much less likely that you have two failing thermistors. A thermistor is just a resistor—it doesn’t typically start reading correctly again simply because the refrigerator was unplugged for a few minutes.
Even new boards can be faulty, especially aftermarket versions.
If the microcontroller locks up or the analog-to-digital converter stops reading the thermistor circuits correctly, the board can “think” the refrigerator is much colder than it really is and stop running the compressor.
The fact that a power reset restores normal operation points strongly toward this possibility.
Intermittent power supply issue on the control board
Since you mentioned the original board had a burnt area, inspect the new board closely for cold solder joints or overheated components.
If you’re comfortable working with electronics, you can monitor the low-voltage DC supply on the board while the failure occurs to see if it remains stable.
Intermittent wiring or connector issue
Less likely since both compartments are affected simultaneously, but still worth checking.
Inspect every connector from the cabinet to the control board for corrosion, loose terminals, or pins that have backed out of the connector.
Thermistors (least likely)
It would be extremely unusual for both thermistors to fail in the same way at the same time and then both recover after a reboot.
Since you’re teaching your son diagnostics, here’s the approach I’d take:
Step 1: Verify the thermistors independently
Unplug the refrigerator and disconnect each thermistor from the control board.
Measure its resistance and compare it to the GE thermistor chart. At approximately:
32°F (0°C): ~16.3 kΩ
41°F (5°C): ~12.7 kΩ
50°F (10°C): ~9.9 kΩ
77°F (25°C): ~5.0 kΩ
Both thermistors should measure close to the expected value for their actual temperature.
Step 2: Measure at the control board
Leave the thermistors connected and unplug the refrigerator.
Measure the resistance from the corresponding thermistor pins on the back of the control board connector.
The readings should closely match what you measured directly at the thermistors. If they don’t, you have a wiring issue.
Step 3: Compare during a failure
The next time the refrigerator thinks the freezer is 9°F while it’s actually around 38°F:
Don’t unplug it immediately.
Measure the thermistor resistance at the control board.
If the resistance matches the actual temperature but the display is wrong, you’ve essentially proven the control board is misinterpreting the sensor input.
Step 4: Check the compressor command
Since the compressor wasn’t running during the warm condition, verify whether the board is actually sending power to the compressor relay.
If the board isn’t commanding the compressor on despite the refrigerator being warm, that further points to a control board failure.
If it is commanding the compressor but the compressor isn’t running, then you’d continue diagnosing the compressor circuit.
My suspicion
Given that:
both temperature readings fail together,
both recover after removing power,
the compressor starts normally after the reboot,
and the refrigerator works normally until the problem returns,
I’d put the odds at roughly:
75% Defective replacement control board
20% Intermittent connection between the board and sensor circuits
5% Thermistor problem
One last question that could help narrow it down:
Was the replacement control board a genuine GE/OEM board, or was it an aftermarket replacement? Aftermarket GE refrigerator boards can occasionally exhibit intermittent issues like the one you’re seeing
Check each thermistor at the point it connects to the board, and then check it at the actual thermistor where it is mounted in the box. If the thermistor reads within range with both readings, then the thermistor is likely good, and the board would be the culprit. But if it is out of range with either the thermistor reading, the wiring would be the issue, and would need to be repaired or replaced.
Thermistors tested okay in ice water (13.2 Ohms, 11.7 Ohms and 12.6 Ohms) using Fluke multimeter. From what I can tell there is no stable DC 5 V reference voltage for reading thermistors which is why the main board is not reported accurate values. It could be bad 5V voltage regulator or something else but I have to stop at this point, too much time wasted.
Going to order a new fridge, maybe from Costco? They deliver for free and take the old fridge away. But I was thinking I want the simplest fridge possible with no digital controls or electronics, just bare bones so its easier to diagnose and fix. Any suggestions?
Not much any more basic Refrigerators.My friend just bought a very basic freezer on top Refrigerator made by Frigidaire.French doors and side by side I can’t think of any without computers!
So far it looks like my best option is a fridge with freezer on top with all very basic controls. Apparently Kenmore still makes very basic fridges and I think Frigidaire. Please chime in if you have a suggestion or any warnings on either brand.
Based on this experience, I would say we are throwing away fridges in landfills due to stupid little digital control boards that in no way are helping anybody or the environment. Its like companies added technology (in this case digital boards/chips) to make the fridge more “advanced” but in fact now the fridge more fragile when the underlying technology (refrigeration) is completely fine. Its pisses me off this is where everything is going (washer, fridges, cars, you name it).