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Whirlpool WRF736SDAB11 refrigerator section is either too cold or too warm, freezer works fine

jon@8000

Premium Member
Joined
Aug 20, 2021
Messages
5
Location
Massachusetts
Model Number
WRF736SDAB11
Brand
Whirlpool
Age
6-10 years
Hi, My Whirlpool WRF736SDAB11 looks to have a problem with the air damper not working, it gets stuck either in the open or closed position. The evaporator fan is working, and there's no ice buildup. I pulled things apart and I can't seem to measure any voltage at the input to the damper motor. I pulled the damper control assembly out and hooked it directly to 120VAC and it cycles open and closed continuously. Not sure, but I'm assuming this is how it's supposed to work? If so, it looks like the damper assembly is working. So now I'm thinking it's the control board. The first time I put the unit into test mode #3 the damper was cycling open and closed, but now when I put it into test mode#3 it only blinks 02, and SW3 doesn't do anything.

Has anyone ever seen this problem before that's related to the control board? Is there any way you know of to be very confident that the problem is in the control board?

I looked at a pretty recent thread on this site and it mentioned putting the unit into test mode #3 and checking voltage on the control board at P2-2 to P1-2 and P2-5 to P1-2. It mentioned that there should be about 120VAC between those pins. I tried this and measured nothing from either P2 pin to P1-2. I do measure 120VAC if I go from those P2 pins to P1-1. I have the wiring diagram provided by Whirlpool, but since I have no schematic of the control board I don't know what points are actually being measured in the control board circuit.

I'm trying to determine if it's definitely the control board. Some websites I looked at indicated that control board failures are rare. So I want to be confident before I buy this expensive part.

Thank you for any help!
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
122,630
Location
McMullen Valley, Arizona
Hi, I'm attaching your tech. data sheet below.

I boxed in RED what the AIR BAFFLE connecter pins should be.
Screenshot 2021-08-20 14.30.09.png
 

Attachments

  • W10568023 .pdf
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jon@8000

Premium Member
Joined
Aug 20, 2021
Messages
5
Location
Massachusetts
Hi Jake, Thanks so much for responding and for this info. So if I turn on service test 3 and measure from P2-2 to P1-2 and P2-5 to P1-2, I should read 120VAC for both cases? When I tried this earlier today, the meter basically measured zero or actually a very low voltage. Do you know what it means in the above chart when it says "Step 3"? I don't understand that. As it is now, service test 3 doesn't seem to be working since it just flashes 02, the damper doesn't move, and SW3 doesn't do anything. It would be great to get any further thoughts or suggestions you may have about this.
Thanks again!
Jon
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
122,630
Location
McMullen Valley, Arizona
Do you know what it means in the above chart when it says "Step 3"?
They meant to say TEST 3 I imagine.
Service Test - 3 Evaporator fan motor and air baffle motor
--->Turn on the FC Evaporator Fan and Air Baffle and monitor the Air Baffle feedback. SW3 (01= Fan On / Air Baffle Open. 02 =Fan ON / Air Baffle Closed.)

If you are getting low volts or no volts in SERVICE TEST 3 at the control board pin locations, then your control board is bad.

You should be getting 115 volts per that chart I posted above.

Here's the control board for your model:
WPW10589838 Electronic Control Board


Jake
 

jon@8000

Premium Member
Joined
Aug 20, 2021
Messages
5
Location
Massachusetts
Thanks Jake. I get no voltage on those pins when I set it for service test 3. I'm assuming I'm supposed to measure it with all of the connectors plugged in? If I unplug the damper assembly, I do measure some voltage on those pins, but not 115V. So I guess I have a bad control board. Nothing looks burnt on it, but it must have a defective component. Do you know if I could get the full schematic for this board anywhere?

Thanks for your help, much appreciated!

Jon
 

rickgburton

Appliance Tech - Moderator
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Jul 11, 2006
Messages
43,669
Location
Murray, Utah 84107, United States
The board is faulty. Board schematics don’t exist, That’s where you transition from appliance tech to electronics tech. Very few bad boards have a burn mark unless something was shorted. The problem is probably in the on board MICOM’s and other related components.
 

jon@8000

Premium Member
Joined
Aug 20, 2021
Messages
5
Location
Massachusetts
Hi Rick, Thanks for providing this input. It's unfortunate that schematics aren't available to the general public. It could be a $1 part that failed, and since I have an EE background, there's a decent chance I could fix it myself, but without a schematic there's no hope of doing so.
Thanks again,
Jon
 

rickgburton

Appliance Tech - Moderator
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I have never been able to find a board schematic. Most manufactures outsource the PC boards. They’re made somewhere else. Maybe the name is on the PC board. They should have a board schematic. Getting one is probably a different story. I see lately, more and more pc board rebuilders. I wonder where they get a schematic or if they even need one.
 

jon@8000

Premium Member
Joined
Aug 20, 2021
Messages
5
Location
Massachusetts
Good point. You're right, I do see a couple of places on Ebay that offer repair service. I wondered how they get schematics, but they must, along with a Bill of Material for component information. There's a name "Aries" on my control board. Perhaps that's related to the outsource vendor.
 

rickgburton

Appliance Tech - Moderator
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Even if you find the board manufacturer they won’t give up a schematic unless you have a wholesale account with them.
 
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