FIXED KRFC704FBS01 Cold Freezer, but the top of the fridge is warm when the bottom is cold.

[Yang]

Model Number

KRFC704FBS01

Brand

KitchenAid

Age

1-5 years

Hello,

My refrigerator is warm on the top of the fridge while the freezer works well. I notice there is a thermistor in the pantry drawer at the bottom of the fridge (it is cold there) and it shows the exact temperature there when I run the diagnose mode.

But the evaporator fan doesn't run to circle the warm air at the top of the fridge.

I did research and read the forum trying to find the solution to solve the problems of my refrigerator.
I think this one is very similar:

FIXED - KitchenAid KRFC704FSS01 Cold Freezer Warm Fridge Issue, But with Data

Hello There Appliance Blog, I have read through the stickies and searched the forum and made an attempt to isolate my issue the best I can. I need a little help to nail down the fault. I have a freezer working great with a warm fridge. Ice maker in the door is working great. The fridge has...

www.applianceblog.com

but i have different data as show below.

Service Test 01 RC Thermistor = 43
Service Test 02 FC Thermistor = -13
Service Test 03 RC Evaporator Thermistor = 77
Service Test 04 First FC Evaporator Thermistor = -18.4
Service Test 05 Pantry Thermistor = 34

Pin Voltages:
P8. P8-1 to P8-2 (5VDC) RC EVAP THERMISTOR OUTPUT = 1.5 - 5VDC (MAXIMUM) This reads 4.98V
P8. P8-3 to P8-4 (5VDC) FC EVAP OUT THERMISTOR OUTPUT = 1.5 - 5VDC (MAXIMUM) This reads 4.98V

P14. P14-1 to P14-2 (12.7VDC) FC EVAP FAN OUTPUT This reads 12.6 volts when fan is on
P14. P14-3 to P14-4 (12.7VDC) RC EVAP FAN OUTPUT This reads 12.6 volts when fan is on

P5. P5-1 to P5-2 (5VDC) FC THERMISTOR OUTPUT = 1.5 - 5VDC (MAXIMUM) This reads 4.98V
P5. P5-3 to P5-4 (5VDC) RC THERMISTOR OUTPUT = 1.5 - 5VDC (MAXIMUM) This reads 4.98V

I removed the cover to see the evaporator in the fridge and found the ice built up at the top. (I defrosted it manually two days ago)

Any ideas about what I should do for the next step?

thanks! looking forward to seeing your replies.

 

[Jake]

Like I mentioned in post #2 of that other thread the thermistor seems to be the problem, you said on yours--->Service Test 03 RC Evaporator Thermistor = 77

77 degrees F on the evap. thermistor? Did you take a real time temperature of the evap. thermistor as well?

RC EVAP FAN OUTPUT This reads 12.6 volts when fan is on

So you are getting the proper voltage to your RC evaporator fan motor. So your control board is good.

So I'd order the same exact part and should fix it like it fixed his in that other thread.

You can only get the RC thermistor only when you order the complete RC evaporator fan motor and cover assembly W11395558:

Whirlpool W11395558 Cover-Evap (AP6980049) - AppliancePartsPros.com

Cover-evap W11395558 / AP6980049 made by Whirlpool

click.linksynergy.com

Jake

 

[Yang]

Thanks for your reply. Appreciated.

I didn't take the real temperature on the evaporator thermistor when the service test shows 77F. But i removed the evaporator cover quickly after the test, the evaporator thermistor has been covered with the ice at that time as shown in the picture above. It should be around 32F instead of 77F, even though i didn't take the real temperature.

Besides, do you have the thermistor resistance chart for reference?
I did test the resistance of RC thermistor and RC evaporator thermistor under room temperature(around 65F). One shows around 3k+Ω and another one 1K+Ω. I forgot the exact number. But they varies a lot.

 

[Jake]

do you have the thermistor resistance chart for reference?

This should be it here:

Thermistor Temperature vs Resistance Chart

Temperature vs resistance data for this particular thermistor WP2188819 common to many Kenmore/Whirlpool/KitchenAid models is readily available. However it does not extend below -5F or provide a lot of detailed values for testing at near room temperature or freezing. So I've taken this limited...

www.applianceblog.com

Jake

 

[Yang]

Thanks, Jake. This is very helpful and it narrows the causes of the issue down to the evaporator thermistor. When I test the resistance of the eva. thermistor under RT and it only shows 1.3KΩ which is absolutely wrong (the correct value should be around 3.6KΩ). I found a good thermistor by chance and replaced it by cutting the wires (trying to give it a shot before ordering the whole assembly). Then it works perfectly now and no ice build-up on the evaporator either.

 

[Jake]

Sounds good Yang.

Let us know if it keeps working good with the thermistor you replaced only, if so please post the part number of it so others will know too.

Jake

 

[Yang]

Hi Jake,
it has been more than a month and the refrigerator still works well. I believe the thermistor did solve the problem.
The thermistor part number is W10316760
Hope this could help those who have this similar issue.

 

[Jake]

Thanks Yang for letting us know that.

Here's that thermistor, in case others need it too:
Temperature Sensor W10316760


Jake