FIXED WRF736SDAM13 Freezer defrost problem - iced up

flensr

Premium Member
Joined
Oct 31, 2017
Messages
13
Location
Los Angeles
Model
WRF736SDAM13
Brand
Whirlpool
Age
1-5 years
Hello,

I have a whirlpool WRF736SDAM13 fridge. It started making a weird grumbling noise and the fridge wouldn't stay cool. Initial investigation shows that the freezer cooling coils are all frozen and the ice finally froze up to where the fan can't force cold air up into the fridge any longer. It's defrosting now and I have it partially disassembled. The rear cover panel is frozen to the coils so while I'm waiting for that to thaw, I figured I'd ask for some opinions on where to start diagnosing. I did call a fridge repair guy and he wants about $650 to replace the control board and main thermostat. $350 of that is parts, $200 labor, the rest taxes and shipping.

I'm not convinced. The heating element could have failed, and the defrost thermostat could also have failed. Where the control board is $299, the thermostat is about $40 ($140ish if I buy it along with the fan unit) and the heating element is likewise well under $100. I figure any of those parts could have caused this icing -- the defrost thermostat, the defrost heating element, the primary thermostat, or the control board.

Is there any way to narrow this down? I ran across a little howto regarding using a multimeter to test the defrost thermostat but I don't know how to test the defrost heating element or anything else. I'm trying to avoid just replacing everything one piece at a time, especially since replacing those thermostats and thermocouples require snipping out the old ones and splicing in the new, which is kind of a pain and introduces a potential new failure point.

EDIT - I have the cover off and there is a lot of ice in there, so much that I don't think this failed recently. It was only yesterday that I noticed the grumbling sound and the fridge temp was lower than it should be, so it's probably been building up ice for a while before it caused symptoms. Now I'm wondering if I should just replace the fan unit too since it comes with the defrost thermostat anyhow and the fan was probably running a lot more than usual.

I don't know how to test this thing after it's defrosted. Ideas?

Any advice would be appreciated. My wife wants her fridge back, I don't want to spend $1000+ replacing everything one part at a time. Thanks!
 

Jake

Appliance Tech - Admin
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Messages
99,161
Location
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Hi,

Here's the tech. data sheet for your model: https://www.dropbox.com/s/wb18uu5rpjszs41/WRF736SDAM1%20Tech%20Sheet.pdf?dl=0 Put it in diagnostics and see if your defrost thermostat(bi-metal) is working properly, and the defrost heater should come on in that Service Test 6.

Make sure the defrost thermostat is covered in frost before you do the diagnostics. Because it has to be frosty for it to be closed and for the heating element to come ON.

If its not frosty, Watch this video: Defrost Thermostat Testing Video Leave it in the ice water for at least 5 minutes before ohm testing it

The defrost thermostat on this model only comes with the evaporator fan motor.

Here it is below, its the black round part with the metal clip on it.

Evaporator Fan Motor WPW10514110


Let us know what you find.

Jake
 

flensr

Premium Member
Joined
Oct 31, 2017
Messages
13
Location
Los Angeles
Thanks Jake. I did this, and the code keeps coming back 02 for defrost thermostat open and the heater doesn't come on. I can't get a multimeter on the thermostat to double-check without cutting out the thermostat, so I'll have to make that my next step I suppose.

For some reason the thermostat for this fridge can't be purchased by itself, it only comes in the motor kit you showed in your post, $130ish for a $10 thermostat (ugh). I'm thinking maybe I can try a different similar thermostat first so based on the numbers in the tech sheet I just ordered a generic W10225581 replacement.
 

Jake

Appliance Tech - Admin
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Messages
99,161
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code keeps coming back 02 for defrost thermostat open and the heater doesn't come on.
Did you make sure the defrost thermostat was FROSTY or in ICE WATER before doing that test, that's a must.:)

You really need to order what they say to order, if they made it to work separately, they would of made the defrost thermostat a seperate part you could buy.

I can't help you if you don't replace the parts with OEM parts per Whirlpool. Replacing parts that don't match their parts list is asking for trouble.

Jake
 

flensr

Premium Member
Joined
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Messages
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Location
Los Angeles
Yea, I left the fridge running overnight, temp inside was a bit below zero for about 6 hours before I ran the test so it should have been about as cold as it'll ever get. Spec says 12F +/- 7F and the thermostat itself has 38F on the side for closed temp, so cold soaked below 0F should have closed it.

I understand the bit about not using OEM approved parts. Still, $130 for a $10 thermostat is really effed up even for the appliance repair biz. I'm going to try the $10 option using a similar part before plunking down the extra money. Its a simple bimetallic switch for crying out loud, and whirlpool has a unique part for that switch for many other fridges with identical setups. So I'll try that and if it doesn't work I'll try something else.

The repair guy I called out wanted to start with the $299 control board which takes 15 min to swap, plus a $50 thermocouple which takes an hour, instead of running the diag. $10 vs. the $650 the repair guy wanted (and which wouldn't have fixed it) is a reasonable risk at this point. Once I get the thermostat swapped I'll do a good test of the next least expensive part (the heater itself). Work my way cheapest to most expensive instead of the other way around.
 
Last edited:

Jake

Appliance Tech - Admin
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Messages
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I know they charge a lot in Los Angeles for appliance repair work, here in Arizona I charge much much less, because the cost of living is much less expensive here.

As appliance techs we use the OEM parts, mainly because we hate repeat service calls, I don't want the customer to call back 3 weeks later saying its doing the same thing.

So its up to you, I hope it does fix for you if you go that $10 route.

Jake
 

flensr

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Messages
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Location
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Update. A replacement bimetal thermostat showed up in the mail so I took the old one out. The first thing I did was test the old one while it was still cold, and it tested GOOD. Argh, I cut the wires off too short to be able to put it back in without soldering on extensions. Oops.

Next I bypassed the heater thermostat, but the fridge diag mode still reported the thermostat OPEN. I traced the wires back to the control unit, pulled the appropriate harness, and the wiring harness from the thermostat to the control unit tested GOOD. I checked heater element continuity and that also tested GOOD.

So basically everything I can test and/or bypass independently tested good but the diagnostic mode self-test still reports the thermostat circuit is OPEN not CLOSED.

Also, when I enter the defrost heater test mode, I hear a single CLICK from a relay. I thought there should be 2 clicks but I'm hearing only one.

Does that mean I'm stuck with buying a new control unit? That's over $300. I'm inspecting the control board traces to see if I can find a bad solder joint but at this point I'm not hopeful because I don't have a circuit diagram for the control unit. None of the capacitors on the control unit look popped, which is the first thing I look for...

Thanks in advance!
 

flensr

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Messages
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Location
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Ugh I think I might have found a bad solder point in the trace for the heater thermostat. Still looking.
 

flensr

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Joined
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Messages
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Location
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Last update today - I closed up that bad solder joint and it still reports the defrost thermostat as "open" in the diagnostic and the heater element does not come on, even with the thermostat bypassed. Any suggestions before I order a new control board? Thanks in advance!
 

Jake

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Yes, if defrost thermostat was FROSTY before doing that test and it still says open when its closed, then your control board is bad.

Here's the main control board for your model you can order:
WPW10589838 Electronic Control Board


Plus you get $60 credit on your credit card when you return the old one.

Jake
 

flensr

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Messages
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Location
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I installed the board and it seems to be working. I installed the new "incorrect" defrost thermostat (open/close temps are very close to the numbers listed in the tech spec sheet) because I cut the wires off too short on the old one to be able to put it back in without using 2 splices, one of them soldering. It seems to work, reporting open when warm and closed when cold. Defrost heater self-test turns on the heater like it's supposed to now that the new control board is installed. I'm a bit bummed that the old control board is junk because of what is probably a very simple failure (bad solenoid is my guess) but I don't know enough about them to know which one to replace or even how to safely bench-test the solenoids while they're still on the board.

I'll keep the old defrost thermostat around just in case the new one fails. It'll be a hassle but I can splice in longer wires if I really need to use it again.

In any case, thx for the help!
 

Jake

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Joined
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Messages
99,161
Location
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Excellent, glad to hear the new control board fixed it.:)

Thanks for the update!

Jake
 
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