Might seem counter-intuitive but check if the refrigerator compartment door seal is providing a good tight seal.
A faulty seal can cause warmer outside air to enter the compartment and you would think that this would mean that the compartment would be too warm, but this may also fool the control board into thinking that it needs to continue to keep cooling it down, so that it actually becomes too cold.
Place a sheet of paper between the door and the door jamb and with the door closed normally i.e. no pressure on it by you to keep it closed, try pulling it out. It will come out with a bit of an effort, but not that easily and it should definitely not fall out by itself. Do this at various points around the door, top, bottom and both sides. Also check that the door is straight and parallel to the cabinet in case it is a hinge problem causing a faulty alignment of the door.
If the refrigerator door seal is faulty , damaged etc search online for ''W10830162'' (part number for the door "gasket" for your model) to find suppliers that suit you best.
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=== Update (10/29/23) ===
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Hi @mortonce
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Here's the [document|32026|tech sheet] for the refrigerator.
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At least it is as far as this [link|https://www.searspartsdirect.com/model/287no4pfo7-000593/kitchenaid-krfc300ess01-bottom-mount-refrigerator-parts|parts supplier] and Whirlpool are concerned (your model uses Whirlpool parts)
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I'm not convinced as the sheet shows features and components that aren't shown in the parts list e.g. the parts list only shows one thermistor in the freezer (part #17 freezer liner parts diagram) yet there are three thermistors shown in the sheet i.e. refrigerator, freezer and ambient.
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Be that as it may, hopefully the sheet may still be useful.
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Looking at the wiring diagram, the freezer thermistor connects between pins 2 & 4 of connector CH3 on the control board (white/yellow & white/orange wires). The white orange wire is the common wire which also connects to the other? thermistors which appear on pins 1 and 3 of CH3
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You could check for continuity from the thermistor to pins 2 & 4. The sheet also gives the resistance values of the thermistor at certain temperatures as well - see specifications at the beginning
Might seem counter-intuitive but check if the refrigerator compartment door seal is providing a good tight seal.
-
A faulty seal can cause warmer outside air to enter the compartment and you would think that this would mean that the compartment would be too warm, but this may also fool the control board into thinking that it needs to continue to keep cooling it down.
+
A faulty seal can cause warmer outside air to enter the compartment and you would think that this would mean that the compartment would be too warm, but this may also fool the control board into thinking that it needs to continue to keep cooling it down, so that it actually becomes too cold.
Place a sheet of paper between the door and the door jamb and with the door closed normally i.e. no pressure on it by you to keep it closed, try pulling it out. It will come out with a bit of an effort, but not that easily and it should definitely not fall out by itself. Do this at various points around the door, top, bottom and both sides. Also check that the door is straight and parallel to the cabinet in case it is a hinge problem causing a faulty alignment of the door.
If the refrigerator door seal is faulty , damaged etc search online for ''W10830162'' (part number for the door "gasket" for your model) to find suppliers that suit you best.
Hi @mortonce
Might seem counter-intuitive but check if the refrigerator compartment door seal is providing a good tight seal.
A faulty seal can cause warmer outside air to enter the compartment and you would think that this would mean that the compartment would be too warm, but this may also fool the control board into thinking that it needs to continue to keep cooling it down.
Place a sheet of paper between the door and the door jamb and with the door closed normally i.e. no pressure on it by you to keep it closed, try pulling it out. It will come out with a bit of an effort, but not that easily and it should definitely not fall out by itself. Do this at various points around the door, top, bottom and both sides. Also check that the door is straight and parallel to the cabinet in case it is a hinge problem causing a faulty alignment of the door.
If the refrigerator door seal is faulty , damaged etc search online for ''W10830162'' (part number for the door "gasket" for your model) to find suppliers that suit you best.