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Hello all. Before I begin, I realize this is a common issue with many posts that I have read. I have tried to compile all the information I could find and taylor it to my specific model and was hoping someone knowledgable would comment on my plan of attack. BTW, there is indeed a lot of great information on these forums.
Issue: Freezer cold, Fresh Food area warm. Frost on back of freezer. Top 2/3rds of evaporator coils were frozen.First, this model does not appear to have a defrost timer - it’s on the mother board, am I correct on that? Therefore unfortunatly I can not check that timer first, which seems to be the most common cause of error.Steps to fix: 1.Manually defrost. 2.Plug back in. (This is where I'm at now) a. In a perfect world, the coils would have just frozen over from leaving the door open too long and the fridge should be good now. b.However, more than likely after a week the same behavior will come back. In which case… 3.Defrost again. 4.Check heater for continuity (http://youtu.be/311BiD76iYg). If it’s open, the defrost heater is bad and has to be replaced (Part 230, $45). If it has some resistance, then it’s ok… 5.Check the defrost thermostat for continuity (http://youtu.be/zmdsBkO46dk). If it’s open, the defrost thermostat is bad and has to be replaced (Part 240, $28, Install). If it has some resistance, then it’s ok… 6.Replace Mother Board (Part 801, $135). 7.Hope for the best. Note: Does the temperature sensor (Part 243, $9) need to be checked and replaced? Anything else I am missing or maybe doing in the wrong order?Thanks, Kevin
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Hi Kevin, You can start the tests from the main control board. Unplug the refrigerator and pull it out of the wall. Remove the wire from the J9 terminal and unplug the J7 connector. Measure the resistance between the wire removed from J9 terminal and the wire (orange) at the J7-9. Normal reading suppose to be no less than 22 Ohms. If the reading is correct, replace the main control board. If the reading is incorrect, then proceed with the defrost heater and the overtemperature thermostat (you call it "defrost thermostat" but this is wrong) testing. Check the evaporator thermistor by doing the following: Set your meter on a highest setting. Remove the J1 plug and measure the resistance between the wires connected to J1-5 & J1-4. At the same time you have to measure the temperature in the freezer, using a refrigerator thermometer. Post the results. - The main control board Part number: WR55X10942
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Gene, thanks for your help. After just letting the evaporator coils defrost and then plugging back in, the system worked again for about 2 weeks before the fridge side started to warm up again.
This time I defrosted the coils and was able to check the heater and the defrost/overtemperature thermostat. Both had continuity.
So I guess the problem is down to either the the temp sensor/thermister or the board. Could you please elaborate on how to check the board? Is there a schematic so I know which terminal is which? I do not really know which is the J1, J2 , J3, etc.
Thanks.
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Sorry, after I posted that I was able to get to the board and see it is labeled.
I was able to check the heater and the thermostat again directly from the board and confirmed they do have continuity. (about 22ohms)
I tested the thermister and got a reading, but they were about 3-4 kohms. I got the same reading from the board and the actual part. The thermister sat in a couple of ice water on a shelf for a few minutes before I took the readings.
I have read that it should be somewhere near 16.3-16.6 kohms for the thermister. Does this indicate then that this is the bad part, or could my test method have been incorrect? Thanks again.
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I'm assuming you did test the evaporator thermistor. The thermistor resistance reading is incorrect for the iced water temperature (about 32°F-34F). I would recommend to replace this thermistor.
If you did test both thermistors and the reading you posted is for both of them, then replace both thermistors. They are identical.
Gene.
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Yes, it was the evaporator thermister I tested. I just tested it again (with my analog meter) now that the unit is plugged back in and running again. Here are the results from the board, and a thermometer I placed inside:
J1-5 & J1-4: 4 kohms @ -2 F
J1-5 & J1-3: 25 kohms @ 32 F
J1-5 & J1-2: 16 kohms @ 32 F
So it definitely seems that the evaporator thermister is bad. I tested the other two just to see what they would read. I believe those are the fresh food thermisters unless I am mistaken. The second seems a little high, should I replace that too?
I have a new thermister on order to replace the evaporator thermister. It would be great if the $9 part was all that I needed to fix the problem.
Thanks again for your help.
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Originally Posted by: blackbirdMD  ..J1-5 & J1-4: 4 kohms @ -2 F
J1-5 & J1-3: 25 kohms @ 32 F
J1-5 & J1-2: 16 kohms @ 32 F... The first reading is for the evaporator thermistor and is incorrect. The second reading is for the freezer thermistor. Are you sure the temperature inside the freezer was just 32°F at that time? The third reading is for the fresh food compartment and is correct. Gene.
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You're right - the freezer was -2F.
I thought the second reading was for the fresh food compartment. I thought there was 2 in the fresh food compartment, and just one in the freezer (the evaporator).
For the second though, 25 kohms is a bit low for -2F isn't it? I chart I have says it should be up about 48 kohms. Could that one also be bad?
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Originally Posted by: blackbirdMD ...For the second though, 25 kohms is a bit low for -2F isn't it?... Yes, it is. It will be better to replace both of them. All thermistors in your fridge are identical with the same part number. Gene.
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