First time working on a fridge so bear with me, I'm having trouble figuring out why this fridge seems to be over cooling.


Basically when you press the "fridge" button, it displays the target temperature (44*) however when the fridge is actually 26*-30* (per 2 different digital thermometers, infrared and instant read food thermometer). This is causing the water in the water filtration system to freeze and our food to freeze even when on the highest temp setting (44*).

I took it apart. I found 3 thermistors. One is on the defrost heater. Then there is another at the very top of the fridge on the back panel. The 3rd is near the actuator for the CoolSelect Pantry. I checked the thermistor at the top of the back panel and it reads approx 12.6K Ohms when put in ice water, same story with the thermistor in the Cool Select Pantry. They return to approx 5k ohms when at room temperature.

I would tend to think these are what determine when the compressor runs and thus cools down the evaporator coils. Its not an issue I dont think with a stuck relay for the compressor as it does cycle on and off but seems to think the fridge section is warmer than it is. The freezer portion is perfect, temp wise.

Anyone know how this thing determines the current fridge temp? Does it use a combination reading of these sensors I tested today? If these test at the correct resistance readings, does that indicate a problem with the mainboard?





Here is how I was testing the 2 sensors I found:















Here is how far I've disassembled it at the moment in case there is some additional troubleshooting I can do.















I also pulled the back panel where the circuit boards are and reseated all the connections for good measure. Checked for burn marks on the board, did not find anything. Also, here are the 3 back boards, cover removed: Top one seems to have a larger chip on the backside which is probably where most of the logic is I'm guessing, most of the connectors are there.

Thanks denman for the reply. I have some updates.



So I replaced the control board, and the problem remained. I then replaced 2 of the 3 thermistors because they are like 6 bucks a piece. The third is not available locally however I swapped one of the one of the ones I replaced to the 3rd spot as it uses the same connection, no change, fridge is still running at 25-27*, still well below freezing .


I also tested all 3 thermistors in ice water and they read 12.5k ohms or so and a little over 5.5k ohms or so at room temperature. Obviously have several spare thermistors for spare parts at this point I guess.






Here is the front panel right now in regards to temperatures:













I have 2 thermometers in the unit right now, one on the bottom right right is in the freezer and another is in the fridge. The freezer jumps up a bit when opened but then cools down to -5*, exactly what the set point is on the panel. It is working perfectly. I've bumped it up to +3* as well and it stays there like it should. Here are the current temps:













I checked the damper/ at the bottom for the CoolSelect Pantry and it seems to remain in the closed position at all the times I checked it, thus blocking airflow from the freezer compartment.









There is another opening which I assume goes to the freezer section behind the foam/plastic panel where the fridge evaporator is. I'm not sure what that is for.


I'm thinking perhaps the control board was DOA but I really doubt that, I guess its not entirely impossible, not sure if Samsung uses refurbished parts so maybe this one was DOA with the same problem?


Otherwise I'm wondering if perhaps an issue with the power supply board perhaps which fried the replacement control board? If you look at the pic in the first post, the power comes into a small board in the middle then that goes to a larger board with some large capacitors at the bottom, then from there it looks like power gets fed to the control board. I have a multimeter I can use to test various wires if that would be helpful. I put it into diagnostics mode where it flashes 8 8 or what not but didn't see anything flash like I've read it would. I think the fridge itself thinks it is still working as it should.



I have another control board on order which will arrive Monday but am a little scared to pop it in if say I have a bad power supply board which would then fry the 2nd replacement control board.



Any other troubleshooting ideas are welcome, I'm open to anything.

Where you able to fix the issue with your fridge? I am experiencing the same problem and I am at a lost on what to do. Your response is greatly appreciated.

Hi sseiyah,

Were you able to figure out the problem? I am having the exact same problem with this model fridge so would really like to hear the root cause if you got it working

Cheers,

Typo

I'm having the same issue with samsung rf263beaesr/aa and I've downloaded the service manual for it and found that a sensor is reading about 0 volts and should be between 1.2 and 5. The sensors says 5:Icemaker-Sensor on next to last page and you check it on the computer board at check points 1-7. I tried to unplug the ice maker auger and this lets is go up to 5 volts and check the resistance on the thermister and it's about 10k. Then I thought maybe it's shorted out to the motor and took it all apart and it wasn't. I'm still leary of replacing the auger assy but might try it. I also try to leave the ice maker plug and it complained defroster bad or something like that. I did noticed some talk about updated ice maker parts and even a different computer board too.

like the auger Part Number DA97-12540G (AP6025062) replaces PS11758619, DA97-12540A.