MayTag Dishwasher Control Panel doesnt work

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  #1  
Old 03-14-07, 08:43 PM
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MayTag Dishwasher Control Panel doesnt work

We use our dishwasher only about once every 2 weeks.
Yesterday, it refused to work.
The HEAVY CYCLE button would light, but not the NORMAL, LIGHT, or RINSE buttons.

Pressing the START button and nothing happens.

On the right side the Lock and Dry buttons would light if the heavy cycle button was lit.

I tried latching and relatching the door, but nothing happened.

any ideas?

THANKS

I have unscrewed the panel on the door, but don't know what to look for...
 
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  #2  
Old 03-15-07, 02:28 PM
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Originally Posted by visoredge View Post
We use our dishwasher only about once every 2 weeks.
Yesterday, it refused to work.
The HEAVY CYCLE button would light, but not the NORMAL, LIGHT, or RINSE buttons.

Pressing the START button and nothing happens.

On the right side the Lock and Dry buttons would light if the heavy cycle button was lit.

I tried latching and relatching the door, but nothing happened.

any ideas?

THANKS

I have unscrewed the panel on the door, but don't know what to look for...
You didn't say if it started in Heavy cycle. You only mentioned about the light.

Do you have a wiring diagram on the inside part of your bottom toe plate if you remove the toeplate?

I think you have a nuisancey but not costly problem. Sounds like a bad switch. I can't tell you which one though.

Do you have a voltmeter for testing? If you have no power at any setting you really need to test the door switch first.
 
  #3  
Old 03-15-07, 10:44 PM
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Thanks for the post, no it does not run in heavy cycle.
I'll have to unscrew the toe plate. Is that the standard location for a wiring diagram?

I do have a voltmeter, how do I test the door switch? (but, if this was a problem, wouldn't it render ALL the buttons/lights inoperable?)

Thanks
 
  #4  
Old 03-16-07, 04:30 PM
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Yes, to your first paragraph.

In testing the door switch with a voltmeter, you want to first establish if you have 120 coming into one of the door switch wires. Put one probe on either wire (pick one). Then put your other probe to a ground, while your meter is set to the 250 volt range, to see if you have 110. If there is no presence of 110, probe the other wire. If you have established that 110 is in one of the wires there, then you have to test the switch itself. Now switch your meter to "ohms" and with the diswhasher breaker in your panel box turned off, ohm's test the switch by manually operating the latch mechanism simulating the closed door position. You shoujld have no resistance in this test, whjen yor meter probes are on each of the connectors on the switch at the same time. (I always prefer to disconnect one wire so as to not get some backfeed, skewing the results) Your analog? meter will go all the way to the right if the switch is good, or stay all the way to the left without moving, if the switch is bad.
 
  #5  
Old 03-16-07, 09:30 PM
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Thanks!
Found the wiring diagram..
I checked the incoming voltage, reads 110

WIth circuit breaker OFF, and meter set to Ohms, I get "1" as the reading between the door switch metal. SO this means "infinite" resistance, so no circuit.
Perhaps the door switch is broken?


what should i try next?
Is there a safe way to put a wire between the white and black wire on the door switch to see if this fixes the problem?
 

Last edited by visoredge; 03-16-07 at 09:42 PM.
  #6  
Old 03-17-07, 11:52 AM
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In ohm testing you have to forget the wires now and concentrate on the switch's terminals with one of the wires temporarily pulled off. With one test lead on one terminal, and the other test lead on the other terminal. If you got 1 ohm, in this test, it would mean the switch is good. That means very little resistance.

You can bypass the switch by jumpering the two wires (connecting them together). But you'd have to do so with the power to the dishwasher off! Or else you'd possibley get sprayed with water when it came on, while you are jumpering with the door open!

But you should not have to jumper the wires if you know you are getting the 110 in the one wire, but then, make sure we are on the same page regarding ohming out the switch itself. Do you have an analog or digital voltmeter? On an analog one, the needle is way to the left when in the off position. If you contact two terminals and the meter goes all the way to the right, to where it reads 0...and the next over to the left is 1, etc,. that means you have nearly perfect continuity = good switch.
 
  #7  
Old 03-17-07, 11:59 AM
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Do you have a separate start button that is separate from the dial of the dishwasher timer knob?
 
  #8  
Old 03-17-07, 04:05 PM
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There's no dial,
all push buttons on the front.

On the left to right

HEAVY NORMAL RINSE then the Start/Cancel button, then on the right options for extra rinse, sanitize, drying

I was thinking if it was safe, I could put a wire between the 2 posts on the door switch then try to see if I could activate any of the other buttons (like the normal wash)

Then if that worked, I'd get a new door switch before trying to run the machine
 
  #9  
Old 03-18-07, 11:07 PM
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Oh, BTW I was using a digital multimeter, not analog...

After further testing, I was doing it wrong...

Appears that both door switches are good (the latch has one switch on each side.)

What should I try next?
 

Last edited by visoredge; 03-18-07 at 11:45 PM.
  #10  
Old 03-19-07, 06:05 PM
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I gotta review the thread now that you have explained more stuff.

First of all...do you have a users guide for the machine? Often they have troubleshooting guide with symptoms/cures.

Remove the toekick plate and when you hit the start button in heavy cycle see or feel the motor to try to tell if there is a slight buzz sound or feel. To determine if the motor is stuck.

Also volt and ohms test the start button switch the same method you did with the latch switch.

Also try to find a "common" wire up top that links all the control buttons. Could be red or black as a guess. See if you have full line voltage that leap frogs between the various functions. For example, you may have to push *ONE* of the selector cycle buttons in order for the start button to even work, as a guess on my part. That means that a hot wire has to come off one side of the heavy cycle button and continue to the start button would be my guess.
 

Last edited by DaVeBoy; 03-19-07 at 06:16 PM.
  #11  
Old 03-19-07, 10:47 PM
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THanks for the continued help.
I don't have true "buttons" (if you go to partselect.com and search MDBF550AWW as a model # you'll see what I mean)

I have those "membrane switch" buttons, little indented electronic buttons.
After researching the wiring diagram a bit more here is what I was able to figure out.

My Membrane switch readings appear ok, using my voltmeter/ohmmeter on the Membrane readings per the wiring diagram. Now I'm back at the brain unit...

I ran the "Sales floor demo mode" by pressing the "Extra rinse" button 5 times. ALL the LEDs next to each button light up in order, which means the LEDs work...

I am unable to run the "Manual Function test" or the "Field Service Test" because when I press the start/stop button nothing happens. I dont' hear any whirring when I press the Start button in Heavy Cycle mode.

Perhaps my control board is shorted out somewhere, disabling the start/stop and the "normal wash" buttons.

I wish there was a way to know for sure, I don't want to drop $100 bucks for a part I can't return if it's the wrong one!
 
  #12  
Old 03-20-07, 12:45 PM
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I know what you mean. Been there...often. Always fear putting in an unneeded part you can't take back. That is where the real pros often have the advantage because often they have used or spare ones they can try.

You wouldn't be able to take a digital photo, closeup of the entire inside of that panel would you, and post it on photobucket?

Other than that, it sounds like you have a head on your shoulders for this, and without me actual seeing a wiring diagram or be there to see, my guess is as good as yours.

If power gets to any ONE of the cycle selector buttons, and also to the start button and the start button is good, we must know where the current goes from there...why it is not starting. If it goes inside some computer box from there...hmmmmm...without a real detailed schematic...you might have to chance it....or hire it out. You'd have to find out what they charge and then compare that to a new control box.
 
  #13  
Old 03-20-07, 10:36 PM
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You can see pics on flickr
http://www.flickr.com/photos/kenfused/

the start button is "good" when using my ohmmeter on the ribbon connector per the wiring diagram, but the control board doesn't seem to register this...

thanks!
 
  #14  
Old 03-21-07, 07:11 AM
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Nice 7 pics!

What a nightmare. A machine like this likely has safety features, and I could only start guessing as to what they might be. Short of there being an outright failure in the board (good chance of that), you have to consider that if something was amiss in the machine and the board "knew" that, that it would shut the machine down from not working.

At the start though, I'm trying to think what a malfunction like that could be that would cause it to not start any function of the machine; no water fill, no motor action,... nothing.

Obviously it won't if it senses the door is not latched. I am not certain how complex your latch is, either. Some latching mechanisms may have more than 2 wires (like newer washing machine lid switches, that engage and lock) and require a couple things about the latch to be engaged properly. Only you would know that from what you have seen, and the number of wires involved.

If the machine sensed it was already full of water, I could see it not working either.

If the machine sensed that the timer has not been set to begin a new cycle, I can se it not starting either.

Have you tried to turn off the circuit breaker for a while to "reset' the computer board? You might want to try that if you have not done so.

If I think of anything else, I'll let you know.

You coud call the tech line, but I'm not sure whether Sears does this anymore. SOME comanies have quit their tech help services...but not all.
 
  #15  
Old 03-21-07, 09:24 AM
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I did try turning off the breaker (even left it off for a day) but that didn't do anything.

I am just about ready to go shopping for a new dishwasher.

I think it'll be $70 for a repair guy to come out then, who knows how much for a part and labor to install it... may cost me half of what a new machine would run.

Darn!
 
  #16  
Old 03-21-07, 05:21 PM
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No troubleshooting manual, eh?

Sorry I can't help more. This machine looks like quite the minagerie of wiring/solid state circuitry, that would be beyond the scope of most laymen.

Have you TRIED calling Sears to see if someone can't tell you if it's something nearly as simple as reseting the unit?
 
  #17  
Old 03-23-07, 09:38 PM
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Guess I'll make a few phone calls before going shopping!
Thanks for all your help!
 
  #18  
Old 03-24-07, 03:07 PM
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We try. But soemtimes come up short.

I'd have to admit that if the machine was mine, I'd probably have a tough time with diagnosing yours for sure. About all you can do, I think, is to rule out all the switches and every component that has wires going to it that is not the board. Then after that, it almost has to be the board. But I bet that is one pricey sucker, and one would have to make a misdiagnosis on it, and not have that be the problem.

Dishwashers are not a necessary appliance, and because of that, one can take the time to make calls...perhaps even request a copy of a schematic...preferably the type where you can follow the wiring layout. One kind you can kind of follow, and the other kind you really need to be schooled in it.
 
  #19  
Old 03-30-07, 07:31 PM
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A similar problem

This may be too late to help, but I had an identical problem with my Maytag MDB7600. I called a repair guy, and he said it was probably the touchpad, and that it would cost about $250 to replace ($150 parts + labor). That seemed like a lot to spend on a 4 year old dishwasher that's already proved itself to be a lemon, but I didn't like the idea of junking it either. I checked with the parts store, and the part was only $65, so I figured I could replace both that and the control board and still come out ahead. (I didn't have a lot of confidence in my ability to diagnose it, and no time, with a dinner for 17 coming in a couple of days.) Based on your thread, and my own intuition that the touchpad wouldn't fail this way (a random collection of buttons failing all at once), I went for the replacing the control board first. I guessed wrong, since the $100 part didn't make a bit of difference. The $65 touchpad was next, and the dishwasher works like a charm now. The repair guy didn't sound to confident, but I guess next time I'll trust the voice of experience.
 
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