FIXED MDB7749AWB2 Maytag Dishwasher Blowing thermal fuses.

Joined
Jun 7, 2019
Messages
7
Location
IN
Model Number
MDB7749AWB2
Brand
Maytag
Age
1-5 years
Thermal fuse blew. Installed a new one, properly with kit. Blew again about 1/2 way through wash cycle on 1st run. Water level is fine, haven't been able to test heater yet as it has water in bottom. Other possible causes ?
 
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Messages
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Location
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Update: Put a jumper across fuse, drained it. Checked wiring, other than some tape residue, they seem fine. Tested heater, checked out ok. No visible signs of a problem on control board.
 
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Think i solved it. Pulled the high limit fuse and tested it, no continuity. Gonna replace both that and thermal fuse and see how it goes.
 

Jake

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Hi Terry,

Sounds like you found the problem, let us know how it goes.

Here's the Hi-Limit thermostat and thermal fuse for your model in case others need them too:

WP661566 High Limit Thermostat


W10258275 Thermal Fuse


Jake
Got a question. When i was testing the thermostat, it showed 0 at room temp, like it should. But when i tested at hi temp, at about 207F it showed infinity but then started showing erratic resistance starting around 6 ohms. Is this normal ? It's like it initially opened, but then closed part way allowing some power through. I should note that it never did show infinity again after about 5 more minutes of testing.
 
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Jake

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When it gets to the set temperature stamped on the high-limit thermostat it will open, meaning no continuity at all.:)

Jake
 
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Please excuse my ignorance but, there is not a temperature stamped on this thermostat that i can find, unless its in code. What is stamped on it is : PW-2N, W10339474, 8101. Then on the dark side it is : PCC, 23, PW-2. The PN cross checks with the PN you gave me. So all good there. So i'm just gonna go with it's bad. lol Even if that's not the problem, it is 5 or so years old and wouldn't hurt to replace. Worst case, i would have to replace the control board and have a new thermostat. ;)
 

Jake

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Yes, I forgot this one doesn't have the max temp stamped on it.

When you replaced the thermal fuse did you replace the wires that came with it? If not, you will have to do that or it will keep blowing out.

Jake
 
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Dishwasher made it through a full cycle, with the oven on right next to it. Gonna say its fixed. I found it odd with all the research i did into this online, no one seemed to say anything about the switch failing at high temp. All i could find is if your dishes weren't drying properly. So for folks having this problem, it's worth investigating this.
 

Jake

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Sounds good Terry, glad your back in business.:)

Thanks for the update!

I found it odd with all the research i did into this online, no one seemed to say anything about the switch failing at high temp.
Its very rare to ever see that hi-limit thermostat fail by overheating, usually when it fails it won't heat at all.:)

I've only seen that happen once or twice in the last 32 years.:)

Jake
 
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