I had the wrong service manual linked in the OP, now corrected. My fridge is an N641.3R, not an NX type. Same thermistor specs though.
I just discovered the diagnostic checks in the manual so will check that out. The thermistor has been snipped off, but I get no flashing temp setting, which seems wrong. There is a fault history screen that might say if it saw a fault back when it was running with the suspect thermistor. Will check all that out later.
EDIT--there was a thermistor fault sometime in the past. I erased fault history to start over with the new to us fridge on that.
I can see where Doug has to know all this stuff for so many different models with so many features that have different terminologies in the various manuals. Yipes.
Interesting description on the manual of how the Temp settings work, using the thermistor readings and timing protocols. I see the timing is to have longer time with cooling on and shorter time for cooling off as you go up from 1 to 9. They use "duty cycle" for that in percentage of time on.
But also each setting has its own thermistor reading for when to start and stop the cooling. I can't figure that out. How can the program for duty cycling times in minutes know how long it actually takes to warm back up after it gets to the low temp and shuts down?
From the NX manual:
Setting 2- 18 min on, 42 min off, 30%
Setting 5- 36 min on, 24 min off, 60%
Setting 8- 54 min on, 6 mim off, 90%
So let's say the thermistor reading for turning off is higher for 8 than for 2, so the fin has to be colder before shut off in 8.
Then it is off and the fin warms up. How can the fridge know how long it takes to warm back up? You can have different ambients, effect of venting at the back of the fridge, door sealing, what is in the freezer maybe? It can see when the fin is back up to the restart temp by the thermistor R getting back down to that point.
It does work, so there must be a way it can tell. ?
