Hi @kory71250
Here's the [document|33091|tech sheet] that may help.
Run the diagnostic mode, ''Service tests 1 & 2'' as described to check if both of the temperature thermistors pass or fail.
If they pass it doesn't mean that they're OK, it just means that they're not open circuit or short circuit.
The resistance values of the thermistors at selected temperatures are shown in the tech sheet, so you may have to measure them with a DMM (Ohmmeter function). You can either disconnect the P5 harness plug from the control board and measure back from there to each of the thermistors (P5/1-2 refrigerator, P5/3-4 freezer) or disconnect each thermistor from the harness cable and measure them there. May be better at the control board end, as you don't have to open the refrigerator and lose cool air from each compartment that may alter the temp. ''Disconnect the power from the refrigerator before trying this.''
If both thermistors seem to be OK (with 5% anyway) it may be a control board problem.
Not quite sure but also check if there's 5V DC on board connector P5/1 and P5/3 just to make sure that the correct voltage is being supplied by the board. ''The power needs to be connected to check this''
If you find the problem and it is a faulty part that needs replacing, here's the [https://www.searspartsdirect.com/model/1tyha3y9j6-001198/whirlpool-wrx735sdhz01-bottom-mount-refrigerator-parts|parts list] that is useful.
Locate the wanted part, in the list and note the part number that is shown with it. Search online for the ''part number only'' to find suppliers that suit you best.