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Kelly
Kelly, Appliance Technician
Category: Appliance
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Experience:  Highly accurate diagnostician with over 30 years experience!
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Kenmore elite range. Model 790.46702603, purchased 2007.

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Kenmore elite range. Model 790.46702603, purchased 2007. Erratic heating (took long time, short time, never) followed by no heat. Right now removed cover on circular element in back of range. Set preheat, waited, cycled through both elements on display. Then broil. No apparent heat from anywhere. Previously tested resistance of broiler element, which is about 15 ohms.
JA: How old is your Kenmore range? Have you checked if all the coils and heating elements are working properly?
Customer: Thinking relay board next to test? how?
JA: How long has this been going on with your Kenmore range? What have you tried so far?
Customer: The symptom of preheat to temperature sometimes quick sometimes long been going on for months. Symptom of little/no heat just last several days. Perhaps OK for something, than not, then OK.
JA: Anything else we should know to help you best?
Customer: nope

Thanks for counting on Just Answer to help with your appliance problem. My name is ***** ***** I look forward to helping you!

Sorry to hear you are having appliance trouble, I know how frustrating that can be! Do you have a meter to perform any electrical testing with?

Customer: replied 2 months ago.
ok

Do you have a meter to perform any electrical testing with?

Customer: replied 2 months ago.
I do have a meter, as previously reported the broil element resistance is 15 ohms. Power coming in is 240.

perfect! Can you turn the oven to bake and test between the two wires on the bake element, looking for 240 VAC or 0 VAC, please? Do the same for the broil element, please.

Customer: replied 2 months ago.
ok. will go and do that.

Excellent, thank you! Be careful while testing so not to short your meter leads! ;-)

Customer: replied 2 months ago.
0 volts on both

As I expected, thank you. Please allow me just a few minutes to prepare some information for you, thank you!

If you look on the back of the oven control, you will see a terminal labeled DLB OUT. That is the L2 output to all 3 elements, the bake, broil and convection. One relay controls all of the L2 output and that relay has failed. The oven control will need to be replaced. All connections simply unplug and plug in, making for an easy repair!

The link below is to the part you will need!

https://www.repairclinic.com/PartDetail/Oven-Control-Board/316462821/1197287?rcaid=1000054

Access to the control is gained by removing the knobs and then the retaining nuts below each one of them. Once those plastic nuts are off, the glass panel will come off, exposing the control. See the attached picture.

Please know you may post back at any time should you need further assistance or have follow up questions. I am always happy to help!

Thank you so much!

Hello, I am just following up to see how things were going. How else may I help with this issue?

Customer: replied 2 months ago.
I am greatly disappointed. I received today the control you specified. I also ordered - just in case - a new temperature sensor. I just installed both. Cooktop appears fine. Oven has been on preheat now for 5 minutes - and is completely cold. I am now out $380 in parts, and 2 days toward fixing this range. Any idea what possibly could be the problem?
Customer: replied 2 months ago.
I just replied via the browser session. New parts, oven still cold.

Are you certain you tested the voltages correctly? Are the top burners getting red hot?

Customer: replied 2 months ago.
Pretty sure voltage tests correct. Burners are indeed getting red hot, using them now to prepare dinner.

Well, provided the 240 VAC to the board is correct and the board works, there is nothing else that would make the elements not heat and the voltage be 0 VAC when the oven is on other than a faulty relay on the Oven Control.

See the attached schematic.

Customer: replied 2 months ago.
I will need to look at this later. Sitting down to dinner.

I understand, thank you. I am sorry you are still having trouble with it but please know I will be here to work through it with you until it is working!

Customer: replied 2 months ago.
Not sure how much if any I can do on this yet today. But I am still puzzled about what to do next. A new control is in, so we can assume it works. Burners get red hot which I assume is an additional verification of 240 coming to the range vs 120. Preheat to 350 ran for 30 minutes going through all the normal patterns on the control display. And oven was stone cold.So what should I try next? Could the new control be also faulty? That seems possible but unlikely.

We need to test the voltage to the elements again. Is it still 0 VAC between each of the two wires on each element when the oven is on? The control is energized with both the L1 and L2 leg of the 240 VAC supply. There is an individual relay for each of the elements for the L1 supply and one common one for the L2 supply.

Customer: replied 2 months ago.
Is there an easy place to test incoming 240? I tested at the plug.
Customer: replied 2 months ago.
Still doesn't explain red hot burner and stone cold elements it seems. But I can check that too.

You can test at the cord. Provided no wiring issues in the harness, if you have it at the cord terminals it should be at the control.

Customer: replied 2 months ago.
Cord terminals fine. 120 at each of BW and RW pairs. Will test elements again next. I assume this is with wires connected to element, not disconnected, correct?

Are you getting 240 VAC between the red and black, though, the outside terminals?

Customer: replied 2 months ago.
Also again measured VAC at each of the 3 elements. 0.
Customer: replied 2 months ago.
Using 2 separate meters.

Okay, so you are still missing one side of the voltage supply.

If you have 0 VAC on all 3 elements, then it is the L2 relay or all 3 of the L1 relays, not likely.

Customer: replied 2 months ago.
I looked at the old board. There is what looks like a small resistor labeled R1. It looks as if it overheated . A clue? Something else amiss that is frying resistor and also part of the control? I would hope not...

I don't have access to a board schematic but that is not likely the cause. On the element wires, do you see the connection where they all 3 connect to the brown wire?

Customer: replied 2 months ago.
I will check ...

That is definitely burnt, holy cow!

Customer: replied 2 months ago.
The individual pairs from each element go into a bundle of wires that appear to go under the cooktop to the front of the range. At the back of the range, only brown wires are for the 2 lights and the fan.
Customer: replied 2 months ago.
Convection element fan, not the other fan.

Okay, so you won't be able to disconnect that connector. If we can isolate the L1 and L2 we can figure out which one is not there. But since the element wires are the same color on each terminal that won't work unless we can determine which is L1.

Provided the new control is good, the issue has to be wiring related.

No error codes on the display, right?

Customer: replied 2 months ago.
No error codes. We cooked dinner fine, all these oven tests had the normal animation and so forth. Except code PF when I unplugged it of course.

So it has to be control related. If you are comfortable removing the control so you can test right at the control outputs we can tell real quick with a couple of voltage checks.

Customer: replied 2 months ago.
how do I find wiring problem which seems connected to burnt resistor? If I could return parts I'd just do that and get a new range. But not sure your return policy allows that.
Customer: replied 2 months ago.
I can remove front panel to get access to control, but the wires were tight and plugs didn't leave very much chance to test at those terminals.

I would open the control area and see if you can test the voltages at the control. It is a very difficult area to test at, though.

Customer: replied 2 months ago.
I will open it up...

Okay, thank you for your patience!

Customer: replied 2 months ago.
Ok, I have it open with access.

First test is between L1 IN and L2 IN, looking for 240 VAC.

Customer: replied 2 months ago.
Labels obscured by plugs, will need to hunt.

Should be black and red heavy wires.

Customer: replied 2 months ago.
I see L2 in, don't see the other, using old control to see labels better. L2 in has 2 lugs, one heavy red with white stripe, and a much smaller solid blue.

The L1 is on the side of the board and should have a larger black wire.

It should be over by the smaller plugs.

Customer: replied 2 months ago.
I see a pair of lugs labeled LX. Secondary labels of P5 and P15.

Okay, let's look at the other side. The side farthest from the smaller connectors, there should be a white wire, then an open spot, then a black wire.

Customer: replied 2 months ago.
240 from L2 to each LX.

Okay, so we have 240 VAC to the board. Now, with the oven turned on, measure from the DLB OUT terminal, brown wire and the BAKE yellow wire, looking for 240 VAC, please.

Customer: replied 2 months ago.
I see an 8 pin connector fitting that description, with red wire at other end.

Correct, that black wire is the L1 in. Still see 240 VAC to red?

Customer: replied 2 months ago.
No label DBL OUT. Is it brown wire in that 8 pin connector? It goes red, black, brown, gray, space, black, space, white.

No, the DLB OUT is in the other large connector. Should be red, blue, brown, orange, yellow, blue.

So with bake turned on, you should see 240 VAC from brown to yellow in that connector.

Customer: replied 2 months ago.

In that pic, third from the bottom, L2 OUT.

Brown wire with the white stripe is the L2 OUT.

So with bake turned on, you should see 240 VAC from brown with white stripe to yellow.

Customer: replied 2 months ago.
0

Okay, so that board is bad. You have 240 VAC to it but not out. Is it burnt anywhere like the last one?

Test from the red to the yellow with bake on. Do you read 240 VAC?

Red with white stripe to yellow I mean, sorry.

Customer: replied 2 months ago.
Looks fine

Test from the red with white stripe to the yellow with bake on. Do you read 240 VAC?

Customer: replied 2 months ago.
I still get 0

Do you read 240 VAC from the red with white stripe to the black L1 in that other connector?

Customer: replied 2 months ago.
Which other connector? Board has no L1 label we can see.
Customer: replied 2 months ago.
I am still getting 240 btw that red with stripe and the pair of LX heavy black wires.

See attached page

This one.

Customer: replied 2 months ago.
240

Okay, so that board is bad. Is it showing on the display that it is set to a bake mode? Can you hear the relays clicking when you turn it on?

You are pressing BAKE, selecting temperature then START?

Customer: replied 2 months ago.
No, preheat as always and instructed.

Okay, so that board is bad. You have 240 VAC to it and it is showing you have it programmed correctly but no output. Did you order it new or from eBay or Amazon?

Customer: replied 2 months ago.
we make sure correct element is lit before we remove tester.
Customer: replied 2 months ago.
From your repair clinic link. New.

Okay, so I would call them and tell them it has been tested as defective and request a replacement.

Customer: replied 2 months ago.
I will try that tomorrow.

Okay, sorry this has been such a nightmare for you but from the testing we (you) have done we have shown the board to be faulty.

Customer: replied 2 months ago.
Hopefully vendor will accept that and expedite replacement.

They should, they are food to work with. That is why I refer them.

Customer: replied 2 months ago.
I wonder if they would simply provide a refund. This seems a lot of hassle and the stove at 13 years old is at the typical life expectancy. Getting new parts that are bad does not bode well.

I am not sure, you could phone them. Their number is 1-***-***-****.

Customer: replied 2 months ago.
Remember that picture of my original board and the burnt resistor? I just installed the replacement control board I received yesterday. As before, cooktop checked out fine. Then I started with oven. Within 30 seconds I smelled what seemed like burnt electrical, and oven stone cold. So I opened it up and looked at the control panel. That resistor is GONE, with significant scorch marks around it. SO, either a) I have now experienced 3 bad control boards or b) something else is going on. What is strange is that the first replacement board had close to an hour of bake testing on it, with no smell or evidence around that resistor of anything amiss. Ideas? I know you said a wiring problem might be another possibility in some scenarios at least. But an itermittent wiring problem sounds like a stretch. And with all the protective links and so forth I'd expect in the line side of things and in the control panel, this immediate meltdown seems inconsistent. Thoughts on what to do next?
Customer: replied 2 months ago.
See browser reply for next chapter in this saga. Pic attached.
Customer: replied 2 months ago.
I did also notice that the revision number on the lower circuit board - 12 - was lower than the original -18. So a stretch perhaps is known failure in a board that was fixed more than 13 years ago, but the repair clinic boards are older than that.

Wow! Are you sure none of the elements are shorted to ground on the chassis?

Customer: replied 2 months ago.
Well, nothing has changed in that regard as far as I know. And these last board changes have been done without even moving the range. Simply shutting off the breaker ( vs unplug) and doing all the work from the front.
Customer: replied 2 months ago.
I suppose I could test for that from the back with a simple continuity tester. But if that is the case I wonder why it would be intermittent.

I wonder if there is a wire that may be bare at some spot that is moving enough to short to ground intermittently. That is a high voltage arc failure. I think there is a wiring issue.

Customer: replied 2 months ago.
In that case I think I will hang it up on fixing. Wiring ought not to be moving on a range. And if design is such that there is a place after years of use and heat has become bare, seems it would be hard to find and hard to fix. All visible wiring - with full back panel off, looking with bright light from both back and front under cooktop, looked fine. No visible items of notice.

Heat oftentimes will make the insulation melt and cause intermittent issues, especially if the insulation is breaking down and the wiring is getting close to the oven cavity.

Customer: replied 2 months ago.
I fully understand how that might occur. And IF that happens to be the case with this range, it is a design weakness in the range, still likely difficult to find and fix. Unless you can suggest a specific spot that has been known to cause these problems in this model range. :-)

Nothing for that exact model but wiring issues are almost always around the oven cavity and where the wiring harness bends.

Customer: replied 2 months ago.
how do I get access to all the wires?

The entire top will need to be removed, a pretty major undertaking.

Kelly and other Appliance Specialists are ready to help you
Customer: replied 2 months ago.
I think I will pass.

I don't blame you. It is a project but on an older range it may not be worth the effort unless you are looking at a major remodel to replace it.