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FIXED KRMF706ESS KitchenAid fridge cooling issue - Test 39: Open Evap Thermistor

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craftydad

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Joined
Mar 7, 2021
Messages
16
Location
Schenectady, NY
Model Number
KRMF706ESS01
Brand
KitchenAid
Age
1-5 years
Hi - I may be having the same issue as the member below - the fridge is only a couple of years old, and as of few days ago the fridge is running at 50 degrees, while the freezer runs fine at 0 degrees.
I ran the diagnostics on the front panel and Test 39 RC Evap Thermistor returns 02 - Open.
Is the thermistor in the problem below the RC Evap Thermistor? Does the test point to something else?

I also have a second problem that happened since the day I installed it, but I'd like to fix the cooling problem before everything goes bad.

Pete

KRMF706ESS01 KitchenAid Refrigerator not cooling (freezer working fine)
 

rickgburton

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If the thermistor is open, it's bad. Take it out and measure the resistance. At room temperature or 70°F, you're looking for 3,100Ω to 3,300Ω.
whirlpool-thermistor-w10316760-ap4538142_01_l.jpg
 

craftydad

Premium Member
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Schenectady, NY
Oof! Had to take apart the whole inside! Anyways, I got to the thermistor.
1. It looks like its attached in the right position per the tech bulletin
2. While taking off the bit of tape around the bundle, to see which plug positions align with the thermistor, the red wire just fell out. Literally - no pulling or cutting it - when the tape came off, the red wire dangled.
3. The thermistor tested at 3,600 ohms. A bit above what you stated above.
4. I looked at the schematic and wiring diagram - looks ike the red wired goes to the inverter for the compressor. ??

What to do now? I can pull off the red wire's counterpart from its plug and put in a single wire connection. Not sure what the next step is in fixing it. Fix the red wire and plug it all in and see what happens?

Pete
 

rickgburton

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Thermistor resistance is OK. According to the wiring diagram, the red wire from the evaporator fan motor is connected to a tan wire that runs into a splice with 5-6 other wires. The RC thermistor is the white wire cord and the RC Evaporator thermistor is the black wire cord. If the evaporator thermistor is still reading open you may still have a problem. Was the evaporator fan working?? Is this the same as yours:
Snapshot_6.jpg
 

craftydad

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Messages
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Location
Schenectady, NY
Sorta correct - the fridge is a little different from the schematic. On the fridge, both wires from the thermistor that gets clamped to the evap tube are black. The schematic says pink n light blue. I tested the plugged end of the 2 black wires to get the resistance. I added a single connector to the red wire, snipped off the corresponding tan wire n put a connector on that. It’s an insulated connector. I pushed the connector together, attached the door enuf to connect up the diag panel, turned the breaker back in, and ran several tests. The fan runs, Test 39 (RC Evap Thermistor) got a 01 (pass 😊). I ran tests 01 and 02 (FC thermistor and RC thermistor) - both hit 01 (pass). I ran test 05 (compressor speed) - I really cudnt hear anything, but the results codes changed as they shud.
I’m thinking it was the red wire? It’s a potted plug - maybe the wire was just loose in it or something. Are there any tests I shud perform before we declare victory? Below are the schematic for plug 8 and where the lower 2 wires run off to.
 

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rickgburton

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the fridge is a little different from the schematic.
Wire diagrams and schematics can be tricky but they are both the same.
wires from the thermistor that gets clamped to the evap tube are black. The schematic says pink n light blue.
Both are correct. The schematic doesn't show the connector. On one side of the connector the wires for the evap thermistor are the two black wires in your post 7 picture. They call it a black rip cord, pin #2 and pin #6. Look on the other side of the connector and you'll see one wire connected to the pink and the other wire is connected to the light blue wire.

I think the reason for not cooling was the evaporator fan motor (red wire) wasn't working correctly. I think you fixed it.
 

craftydad

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Schenectady, NY
Thanks!! I'll put it back together and see how she runs. The second problem has to do with the water to the ice tray always turns on when you fill a glass of water. Basically I tested the solenoid actuators up at the top which controls where the incoming water flows - the actual solenoids work fine individually - but the electrical signals they are getting is "both turn on" whenever you fill a glass of water (which makes the ice tray overflow and gets water everywhere). I think the problem is the control board behind the glass filler paddle, as that is where the signal wires are coming from. I've been tempted to just replace it but wanna be sure as much as I can before I do.

Pete
 

rickgburton

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The second problem has to do with the water to the ice tray always turns on when you fill a glass of water. Basically I tested the solenoid actuators up at the top which controls where the incoming water flows - the actual solenoids work fine individually - but the electrical signals they are getting is "both turn on" whenever you fill a glass of water (which makes the ice tray overflow and gets water everywhere). I think the problem is the control board
No, the problem is most likely the one of the isolation diodes failed. The diodes are polarized inline with the isolation water valve behind the machine and the water valve in the FF compartment. The diodes only allow voltage to flow in one direction so both solenoids don't open at the same time. They don't come separately, only with the wire harness. If you want to check them, on the isolation water valve behind the machine, follow the tan wire back until you come to splice with two tan wires and two violet wires. Use a razor blade and cut the black tape from the splice and you'll see something like this:
R-isolation diodes.jpg

This one is from a Frigidaire. Instead of yellow wires you'll have violet wires. Here's the wire harness:

Too bad Radio Shack went out of business. $2 for the diodes. Lol
 

Jake

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36 degrees!!! Woo hoo!! It’s DONATE time!! Thanks!!
Excellent Pete.(y)

Thanks for the donation, I'll see that Rick gets it!

Jake
 

rickgburton

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I’ll check it out tonight.
You can also check the diodes from the main board. Touch one meter lead to any white neutral wire and leave it there. Have some one press the water dispenser lever and touch the other meter lead to P3- Pin 4 (Violet). Your meter should indicate 120 VAC . Now touch the Tan wire on P3- Pin 3. Your meter should indicate 0V. If it indicates 120 VAC, one of the diodes is shorted.
 

rickgburton

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