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GE Dishwasher GDF640HGM2BB New control board, still intermittent power loss

Onorms

Premium Member
Joined
Aug 7, 2022
Messages
10
Location
Florida
Model Number
GDF640HGM2BB
Brand
GE
Age
1-5 years
Having intermittent power issues. I have replaced the control board with a new OEM board, verified that when the DW shuts off I am getting 120v to the board (also verified that LED was blinking constantly), verified continuity in door switch (and even purchased a new one), and verified that DW was level. Was able to run the consumer error mode. Showed a “7“. Research shows water temp circuit has become inoperable. Shutting off power does not always bring it back up. Ran through all of the service modes with no known hiccups. At a loss. I’ve swapped breakers, swapped position in circuit panel, and ran a new electrical run (extension cord) to try to troubleshoot.
 

TRYeager

Premium Member
Joined
Aug 4, 2022
Messages
3
Location
Houston TX
You stated "also verified that LED was blinking constantly" regarding your main control board as if you believe that is what is is supposed to do. Did you find some document to tell you that? The service manual and a tech bulletin for my different model dishwasher that uses the same main control board (configured by the factory differently) states that a continuous blinking of the status LED means a software error and that the main control must be replaced.

That's what my main control did, so I bought a new one. And that's what the new one did, too! And when I replaced the UI board, the main control continued to blink constantly, but my dishwasher was fixed! I'm not saying a UI board is what you need. I'm just pointing out that maybe your original main control is good and you could return your new one just as I did.

Good luck with your repair, but I'm not the right person to help further.
 

Jake

Appliance Tech - Admin
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Messages
132,703
Location
Redmond, Oregon
The UI Board is at the top of the dishwasher door, the machine control board is underneath the dishwasher.

Per your model number, your machine control board is this one: WD21X25732

Your UI Board part number is:

Yes, @TRYeager is correct, when that STATUS LED on the machine control board is blinking on your model, that means its good.

Here's the service manual for your model: https://drive.google.com/file/d/1csheGsbSmPFRON5ThkhhwfvZ6saWoxHc/view?usp=sharing

Look on Page 46, disconnect power to your dishwasher, then check for any water leaks first, if no leaks then remove the heating element wires from the heating element and make sure they are not touching anything, then see if the CSM trips again, if not, then the heating element is the culprit.

I also found this in my documents--->7 Flash or Blink (on UI) during Service Mode A new test indicated by a seven flash pattern (on the UI) is now available to help diagnose the CSM and heater. This test is to help diagnose CSM trips. When the test is started, the control turns on the heater relay (Line), but does not energize the neutral relay. If the CSM trips, the heating element must be replaced.

Here's the heating element for your model:

Jake
 

Onorms

Premium Member
Joined
Aug 7, 2022
Messages
10
Location
Florida
Thank you two for your input. I should have elaborated a little further. As Jake mentioned, the blinking LED shows that the control board is getting 12VDC (I believe, its at least getting power though). I took this as the issue I am having is downstream (internal of dishwasher) and not upstream (dishwasher to electrical panel).

When I activated Service Mode, it automatically started with a ”7” on the UI. The next step allowed me to choose the 7 different trouble shooting steps (blinking LED steps). I ran the all of the trouble shooting steps and they seemed to run correctly. Correctly in the fact that I was able to complete all of the steps and continue onto the next one. After the trouble shooting steps, I was able to run a complete cycle. The very next evening, the DW would not power on. Cycling the breaker numerous times would eventually get it to turn on, however it shutoff at a random time during the cycle. The last time was around 42 minutes remaining on the “normal” cycle.

The service manual is a big help. I appreciate the link to that. I will delve into it and see if there are any other areas I should look into.

Thanks again,
-Matt
 

Jake

Appliance Tech - Admin
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Messages
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Ok Matt, Like I mentioned--->Look on Page 46, disconnect power to your dishwasher, then check for any water leaks first, if no leaks then remove the heating element wires from the heating element and make sure they are not touching anything, then see if the CSM trips again, if not, then the heating element is the culprit.

That heating element is likely bad and causing CSM to trip, thus when you reset the breaker it resets the CSM.

So do what I mentioned to confirm its the heating element tripping the CSM.

Disconnect power to your dishwasher, then check for any water leaks first, if no leaks then remove the heating element wires from the heating element and make sure they are not touching anything, then see if the CSM trips again, if not, then the heating element is the culprit.
 

Onorms

Premium Member
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Aug 7, 2022
Messages
10
Location
Florida
Jake,

Sorry I misunderstood you earlier. There were no leaks so I did as you suggested. It came up after about 10 seconds of having power. I will get the heating element on order. In replacing that element, are there any other items (nuts, gaskets, etc.) that I should replace as well? Thank you for the time you spent on further explaining it to me.

-Matt
 

Jake

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Ok Matt no worries, yes the new heating element should fix it.:)

In replacing that element, are there any other items (nuts, gaskets, etc.) that I should replace as well?
Nope, just the heating element is fine.

This video gives you the general idea of how to replace the heating element:

GE Dishwasher Heating Element Replacement


Let us know how it goes.

Jake
 

Onorms

Premium Member
Joined
Aug 7, 2022
Messages
10
Location
Florida
Hi Jake,

I got the new heating element in and changed without issue. Cycled the breaker and it came on after a 3-5 second delay. DW will run a complete cycle and then stay in the “ready state” for a few hours. I have been successful in running another cycle if it is within 2-3 hours of one finishing. If I wait overnight, the DW will power off and I cannot get it to turn back on without flipping the breaker. Any further ideas?

Thanks again,
-Matt
 

Jake

Appliance Tech - Admin
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Messages
132,703
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Ok Matt, that is very strange, if no water leak and the heating element is new, then it must be a bad machine control board, that's all it can be.

Here's the machine control board for your model: WD21X25732

Wait, didn't you already replace it?

Do you have any other appliances on the same dishwasher circuit? Is that dishwasher circuit GFI or standard?

Jake
 

Onorms

Premium Member
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Aug 7, 2022
Messages
10
Location
Florida
It is a brand new control board. The only other item that is on the DW circuit is the sink disposal. It works all of the time, even when the DW “powers off.”

I have the old control board that was “bad.” I will replace it and see if that changes anything.
 

Onorms

Premium Member
Joined
Aug 7, 2022
Messages
10
Location
Florida
Order of events this evening;
-removed new control board. UI was non responsive but the control board had the green flashing LED on it.
-installed old control board. Old control board had a flashing green LED once hooked to power.
-DW UI had no lights. I could not turn it on after cycling the breaker.
-reinstalled new control board. Verified flashing green LED
-DW will not turn on now/UI is non responsive. Verified 120v at the wires coming out of the wall. Disposal works fine.

In all of my googling trying to find a solution, I came across someone having issues with a timer. Im not sure which board it is located on or if that’s even a possibility of being bad. Something to do with the wiring harness going up to the UI? It seems to be ok and not knocked anywhere.

-Matt
 

Jake

Appliance Tech - Admin
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DW will run a complete cycle and then stay in the “ready state” for a few hours. I have been successful in running another cycle if it is within 2-3 hours of one finishing. If I wait overnight, the DW will power off and I cannot get it to turn back on without flipping the breaker.
So, now it won't come on at all?

If that's the case and the STATUS LED is flashing that indicates there is power to it.

You might have a short in the door wire harness. Check the metal pins in that door wire harness to see if any are bent or backing out AT both ends where each connect to each board.

Here's the door wire harness for your model:

Jake
 

Onorms

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Aug 7, 2022
Messages
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Location
Florida
Hi Jake,

So I checked the wiring harness and pins and everything looked fine. Ohm-ed out the wires (which was rather tough) and I couldn’t find a break. Hooked it all back up and it came right on and I ran a cycle. It will run a complete cycle just fine. The UI becomes unresponsive after a few hours. I did notice that it will beep every 30 minutes or so once a cycle has completed. Im back to flipping the breaker on/off in order for it to come back on. The control board has the blinking LED during the unresponsive UI issue.

Could the ”new” control board be faulty?

Thanks
Matt
 

Jake

Appliance Tech - Admin
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Messages
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Redmond, Oregon

Jake

Appliance Tech - Admin
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Messages
132,703
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Ok, ask them to exchange it for another new one, that one is probably defective.

Jake
 

Onorms

Premium Member
Joined
Aug 7, 2022
Messages
10
Location
Florida
Hi Jake,

New control board replaced. I thought it was working correctly, but just found out that my wife has been cycling the breaker again to get it started. I am at a loss right now. Cycling the breaker will get it started 90% of the time after one or two cycles. The other 10% I have to finesse the cables under the DW to get it to power on. This works most of the time however every 5th cycle or so it will not run a full cycle.

Tonight I tried to get into the service functions. After I got power on the DW, I held “Select Cycle & Start” for 10 seconds. This time all of the leds came on and none of the buttons would do anything. After it seems to time out, the led for the ”locked” function is illuminated, however any key press will remove it. It seems to function properly after that.

The last bit of information I have is that if I get power on and do NOT run a cycle, the DW will beep/sing every 10 minutes or so. It will do this for about an hour and then shut off, requiring a trip to the circuit breaker.

At a loss right now. DW cleans well and I would hate to have to replace a “perfectly good” DW.

Thank you again for your time,
-Matt
 

Jake

Appliance Tech - Admin
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Messages
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Ok Matt,

Look on page 46 CSM DIAGNOSTICS: https://drive.google.com/file/d/1csheGsbSmPFRON5ThkhhwfvZ6saWoxHc/view?usp=sharing Do the flowchart steps.

If everything checks good, then it sounds like possibly a faulty UI Board:

Look at this thread here:

Jake
 

Onorms

Premium Member
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Aug 7, 2022
Messages
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Location
Florida
Hi Jake,

Ran through the CSM diagnostics. Was able to go through the 3 items with no fault. The thread you posted is an almost identical Issue to mine.

The only issue I have right now is that the UI board is back ordered until sometime in October.

Thank you for you help. I feel like we are really close to this one now.

-Matt
 

Jake

Appliance Tech - Admin
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Messages
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Redmond, Oregon
Glad to help Matt!

The only issue I have right now is that the UI board is back ordered until sometime in October.
Yes, that's the only downside.

Jake
 
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