Heater circuit

Dishwasher Repair
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1

I have the blinking light seven times issue. I need to test the heater circuit. I know how to use a multimeter, but unfortunately have no idea how to read a wiring diagram. I would like if at all possible to test the thing without removing it from under the counter. To test the heating element, I figured I would remove it from the dishwasher. From the diagram it seems that the heating element should just pull up out of the dishwasher. Is this correct? I don’t want to force it and break the thing. How much resistance am I looking for?

If the heating element is not the issue, what is the next item I should check?

thanks in advance for the help. You folks provide a great service and I look forward to doing business with you.

2

Thanks for getting back to me so quickly.

I’m having trouble locating where to disconnect the wires from one side of the heating element it seams to me that the wires should connect behind the drain. To get at them I will need to pull the dishwasher out from behind the cabinet. Is this correct? If not (if I understand you correctly I’m wrong), which wires do I disconnect? is there a color or something I can look for to know I’m getting the correct one?

3

I’m having trouble locating where to disconnect the wires from one side of the heating element it seams to me that the wires should connect behind the drain. To get at them I will need to pull the dishwasher out from behind the cabinet. Is this correct?
Yes if you cannot reach them then you may have to pull the unit.
I believe the thermal cutout is near the front so measure that first, if it is an open circuit then you probably have found the fault…
Also you could measure from the Orange wire in the thermal cutout to the White/violet wire at the door switch

If not (if I understand you correctly I’m wrong), which wires do I disconnect? is there a color or something I can look for to know I’m getting the correct one?
It does not matter what side you disconnect. You are just trying to isolate the part you are testing from the rest of the circuit. This ensures that you are measuring just the part and not an alternate/parallel circuit path.

4

I’m getting 10.7 on the heater (measuring from the termianls underneath) and .5 on the high limit thermostat. Do I need the new thermostat? Is there something else I should check?

5

Yes if you look at the wiring diagram you will see the wire from the right hand side of the heating element goes up to one of the door switches.
Check this it should be 0 ohms when the door latch assy is closed.

6

To test this, I test between the wire attached to the heating element on the right side (while facing the dishwasher) and where? Do I need to open it up and get to the door switch?

7

Denman…
I wish I would have found this site earlier than I did. I had a problem with the clean light blinking 7 times on my dishwasher. The heating element was bad, I replaced it. Looking for the wires for the heating element, I must have unknowingly pulled the wires off the high limit. So, the light was still blinking 7 times even after trying to reset. Then we searched the internet and spoke with someone who wanted payment for his advice. He said the high limit was not an issue and advised to change the board. I did with no resolution. Finally, I found this site and read some of your previous posts. I checked the high limit and found the wire loose. I just wanted to thank you so much, your knowledge was very helpful. Still…only wish I would have found this site sooner, like $100 worth of parts sooner. lol.
Also, was wondering if you knew where I might be able to get a tech sheet for my Kenmore dishwasher, model no. 665.16039401? I’d appreciate any more help you can give.

Thanks so much.

8

This should be it
[U]https://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%208535451.pdf[/U]

Thanks for the kind words, always nice to get a pat on the back.

9

I disconnected the orange wire from the heating element, and the orange wire that hits the control board. I get 0 ohms with the latch both closed a and open. I think the circuit is open because it runs past the high limit thermostat. If I measure from the white-violate wire to the other side of the door switch (left side of the dishwasher while facing the front, that runs from the heating element to the door switch), I also get zero both open and closed. What the next step?

10

I disconnected the orange wire from the heating element, and the orange wire that hits the control board. I get 0 ohms with the latch both closed a and open. I think the circuit is open because it runs past the high limit thermostat.
0 ohms is a short not an open. Also I cannot relate this to the wiring diagram as I do not see an orange wire going to the board

If I measure from the white-violate wire to the other side of the door switch (left side of the dishwasher while facing the front, that runs from the heating element to the door switch), I also get zero both open and closed.
This I cannot explain. Seems to indicate that the door switch contacts are welded together (a short, 0 ohms) but this will not cause no heat. The switch must be closed (a short, 0 ohms) for the heater to run.

What the next step?
Are you sure you are reading the meter correctly?

11

I think I should try to explain what I am doing better, as it seems I’m doing something wrong. There are two wires that attach to the heating element, w-v (white with a violate stripe) and OR (orange). There are two switches on the latch, each with two wires attached to it. One has a tan wire and a black with white stripe wire attached to it. The other has a white with violate stripe and a solid white wire attached to it. Am I supposed to be checking that the w-v wire coming off the heating element is at 0 after the door switch (where it hits the white wire? If so I can just check that I get a short when I close the door switch. Does this sound correct?

I just checked that the w-v wire is gives resistance to the door switch (it does) and that the w-v wire to the white wire on the other side of the door switch gives me resistance (when the switch is in its closed position).

While under the thing, I noticed that there are three terminals on the thermistator. Two that look like they connect to the thermostater, and one that is on the bracket. I have the two wires attached to the thermostater (i get .7 of resistance between them). What is the terminal on the bracket for?

I still may be misunderstanding something. Let me know.

Thank you for your patience with all of this.

12

[COLOR=Blue]The other has a white with violate stripe and a solid white wire attached to it. Am I supposed to be checking that the w-v wire coming off the heating element is at 0 after the door switch (where it hits the white wire? If so I can just check that I get a short when I close the door switch. Does this sound correct?

I just checked that the w-v wire is gives resistance to the door switch (it does) and that the w-v wire to the white wire on the other side of the door switch gives me resistance (when the switch is in its closed position).[/COLOR]

Lets check the meter first
Put the meter onto the lowest resistance scale
Should read an open (infinite resistance)
Now short the leads together should read close to zero.
Whatever the value, this now becomes your zero

[COLOR=Magenta]I GET 0.5
[/COLOR]
Am not sure about what resistance you mean, what is the value, it should be close to 0.
Now with one lead on the white/violet wire qt the heating element and the other at the white/violet on the switch. Should be zero. This tells us this wire is OK.

0.7 The wire should be O.K?

Now remove the white wire from the other side of the switch
It is always a good idea to remove at least on wire from any device you are measuring. This ensures that you do not measure an alternate/parallel circuit path instead of the device you want to check.
Not measure from the white/violet to the side of the switch which used to have the wire on it. Should be infinite ohms.
Now activate the switch. Should go to a short (0 ohms).

Before I activate the switch I am at infinite. After, I get 0.6

This does not rule out this component but it does tell us that the switch is OK. It could be that it is not being closed by the latch.

[COLOR=Magenta]I checked the latch prior to taking it apart. I can here an audible click when I close the door. The switch does not have any play in it. It seems to me that its ok, but I may be missing something when checking it.
[/COLOR]
I have the two wires attached to the thermostater (i get .7 of resistance between them).
If this is on the lowest scale (0 to 200 ohms) it is 0.7 ohms, basically 0. On a 20 kilohm scale this could be 700 ohms. The reading is dependent on which scale you are using and the readibility of the meter (number of digits) so when checking for closed contacts you always use the lowest scale.

I am on the 200 ohms scale, so we are getting the zero (similar to the result on the wire and switch). On this scale, the heating element of 10.7 indicates a healthy element (or at least I think it does). seems this is starting to get narrowed down a little.

Thank you for your patience with all of this.
Your patience is probably taking a much worse beating than mine.
I would rather go slow and sure than fast and arc & spark.
I used to work with a guy who was always in a rush, we called him Sparky.
[COLOR=Magenta]
This made me smile. Slow and steady usually ends up faster in the long run. Fewer mistakes.[/COLOR]

13

All the readings in your last post read OK.

Next:
With one lead on the White/Violet at the switch and the other lead on White/Red at the circuit board P6. Take a reading. Should be 10.7 ohms.
This checks that the circuit all the way from the board, through the heater to power is OK.

Next:
Short the White and the White/Violet wires at the switch together.
Tape them so they cannot short to anything.
Try a heat only (dry) cycle
You may have to reinstall the inner door cover.
This removes the door switch not being activated by the latch as a possible cause of your problem.
Check it the heater gets hot. Be careful do not burn your fingers.

If it does not heat up then all that is left is the circuit board is shot.
If it does heat then something is wrong with the latch assembly and the switch is not being closed.

14

How do I run a heat only (dry) cycle?

Before we started, I did open the door after it starting running (while it is heating the water) and the element was warm (not hot enough to burn me but noticeably warm). Also, when it fails, we do not have heated dry turned on (we don’t use heated dry). I’m not sure if that has anything to do with anything though .

Also, My ground came disconnected when I pulled the dishwasher out. Will this cause it not to work properly?

15

I’ll set it running. Do I need to check if the element gets hot or is it enough to see if the light starts blinking again? If I need to check, at what point in the cycle should I do that?

16

With the white and white violet wires shorted together (I had to make a jumper out of a piece of wire to do this) The light started blinking again. I was not able to check if the element got hot (I’m not sure at what point in the cycle to open the thing and check). It does not make it through the entire cycle.

Edited to add: I just opened it up and the heating element is still hot, but the error light (7 blinks) is still going. I don’t think that this was one of the expected results.

Control board?

17

I reset the error (using the self diagnostics) and will reconnect the door switch.

How do I test the thermostater? Also, I would like to confirm I hooked the thermistator back up correctly. I attached the two wires to the thermostater terminals. The third terminal (attached to the bracket) is left open.

18

I reset the error (using the self diagnostics) and will reconnect the door switch.
I would leave this shorted till you run further test

How do I test the thermostater?
Thermistor
Check it for resistance. Item 25 in Pump and Motor section.
Tech sheet gives the acceptable values. Sorry my computer will not load the tech sheet right now.
Note water may drain out if you remove it from the pump.

Thermostat
Also, I would like to confirm I hooked the thermistator back up correctly. I attached the two wires to the thermostater terminals. The third terminal (attached to the bracket) is left open.
Yes this sounds OK

19

if I understand what I am looking at, I am supposed to test the temperature heating circuit.
No you have already checked the heater circuit and it is OK.
This is the temperature measurement circuit.

the resistance should be 48-52K ohms at 77 degrees and 12-13K at 140 degrees.
This is the thermistor which measures the water temperature. If during a water heating cycle it does not see a change in temperature/resistance, it will give you an error

Do I test both high and low? If so how do I do that. Do I pour water into the machine at a known temperature?
Test the low (room temp) first. Remove one wire from it or the plug (if it has one) and measure it. It should be around the room temp resistance area of 48 to 52 Kilohms. If yes you could then measure with some hot water added to see if the resistances drops.
If it does measure 0.5 ohms remove it from the machine.
If it still measures 0.5 ohms when removed, it is faulty and needs to be replaced.

I think we checked this before, and we received .5 ohms (basically zero).
I do not remember testing it.

Am I now supposed to test it with the machine plugged in?
No, it is a standard resistance measurement so power should be off.

If the above component is OK then all that is left is the circuit board and it will have to be replaced.

20

I flipped the thing over and checked. You are correct. We previously checked the high limit thermostat not the thermistor. I checked the resistance at room temperature on the thermistor, and got infinite resistance set at 200, 2k, and 20K (I checked it using all three ranges because I was surprised to be getting infinite). Should I order the thermistor?