Kenmore Rage 79096413400 Infinite switch test - is it getting power?

[cpjxh7]

Model Number: 79096413400
Brand: Sears Kenmore
Age: More than 10 years

Hi. I have a Kenmore range model 79096413400 and the right double element burner and the right back burner are not working. The back right does not work at all and the front outer element does not work, but the inner element does. I have looked on a number of sites and watched several troubleshooting videos.

When I turn the front double element dial (316238201) to dual, just the inner ring lights. When I turn it to single just the inner ring lights, looks like it glows around the very outer edge of the outer ring. It lights for less than 1 minute, clicks and goes out.

I checked the dual burner switch and all checks were good except when set to dual, P2 to 4a is OL. So the switch is bad. The element is good. Testing from the switch wires. 2 to 4a = 42 ohms and 2 to 4 = 4 41.5 ohms. At the element the outer element measures 41.6 ohms and the inner is 42.4 ohms.

QUESTION: The back single burner infinite switch (316436000 ) tests out good as does the element. I even swapped the dial from the left rear and right rear and the left rear still works and the right rear still does not work. Wasn't exactly sure how to test the element from the wires at the dial, but H1 to H2 showed 45.2 ohms, and testing at directly at the element was 40 ish ohms, didn't record the exact reading. I see the this dial shares wires from the front right dial, P2 to L1 and 4 to 2P.

Does the fact that the front right switch is bad cause issues for the back right switch or are the other issues I need to look at? It's like it is not getting power.

L1 is shared with both back burners and comes from the terminal block.

L2 comes from P4 on the Cook top Lockout Board.

H1 goes directly to the element

H2 goes to the limit switch 2A/1A and then to the element

P is shared with the front right switch and comes from P1 on the Cook Top Lockout Board.

I did check the thermal limiter on the burners. 1a to 2a and 1b to 2b are both OL when it is cool, which tests OK.

I read on another site "If the above tests check out and there is no problem in the wiring from the switch to the element and the elements tests as good and you are still not getting any heat from the element, someone will have to verify that 240 volts is getting to the L1 and L2 terminals of the switch. There may be a problem with the range's wiring leading up to the switch. If 240 volts is present at terminals L1 and L2, someone can confirm power out of the switch by checking for 240 volts between switch terminals H1 and H2 with the switch set on "HI"."

Can someone tell me how to test if the switch is getting power to L1 and L2?

Thanks in advance for any help.

[cpjxh7]

Upon more research, I found one post that stated that P = common. If that is true, can I test voltage across L1 to P and L2 to P?  Thanks again!

[Vance R]

8 hours ago, cpjxh7 said:

Can someone tell me how to test if the switch is getting power to L1 and L2?

Using meter set on volts AC just touch the probes to L1 and L2. Word of caution with live tests you can't let probes touch anything else in the area. No crossing terminals with the probes! The readings to expect for right rear are L1 to L2 is 220 vac. H1 to H2 is 200 vac. 1A to H2 is 220 vac. 

[cpjxh7]

Thanks @Vance R ! That's what I thought, but  just wanted to make sure before trying, not a fan of getting shocked and didn't what to do any more damage. 

[cpjxh7]

Well,  L1 to L2 is not 220 vac, I think it read about 18. I swapped out the Cook Top Lockout Board with a spare and there was no change. Any suggestions on what to try next?

[Vance R]

Was the infinite switch in the on position? Just to double check your meter, the termimal block where power comes in the range.  Red to black should be 220 vac, with red to white and black to white being 120 vac each. Next would be to L1 on the infinite switch to P2 on lockout board should be 220 vac. Then with infinite switch in on postion L1 on the infinite switch to P4 on lock out board  should be 220 vac.

[cpjxh7]

Hi @Vance R Yep, tested with the switch on and off. I double checked the meter at the terminal block and also checked the left back burner infinite switch L1 to L2 and both read 220 v with the switch off. I would have thought that L1 and L2 were always hot? I will check L1 to P2 and L1 to P4 tonight and let you know. Thanks again!

[ECtoFix]

If you're reading 220v across L1 & L2 of the switch with it OFF, then 18v with it ON, then you're dropping voltage somewhere in the supply wiring when it's under a load.  I suggest tracing both legs of the source wiring and scrutinize every connection. 

There's an EASIER and more logical approach for doing that by using your voltmeter, but it'd be difficult for me to explain here.  I don't know your skill level in electrical troubleshooting, so it might not make any sense to you.

[ECtoFix]

When I say SOURCE wiring, I'm taking about what supplies that infinite switch at L1 & L2.

[cpjxh7]

Hi @ECtoFix Sorry if the above was not very clear, on the right back burner infinite switch, L1 to L2 did not have 240v with the switch on or off. I'll test again this weekend and take better notes. But I don't think there was much difference in the voltage with the switch on or off.  I thought L1 to L2 should have 240v with the switch off and since it doesn't it didn't make sense to test anything beyond the switch and there is a problem in the source somewhere. As a comparison, I tested L1 to L2 on the left back burner infinite switch and got 240v with the switch off. Hope that clears up what I was trying to explain.

I am not an expert in electrical troubleshooting by any means, but have a neighbor and brother who are, so if you want to give it a shot, feel free. 

Thanks for the help!

[Vance R]

@ ECtoFix

My recommendation for checking L1 to P2 and L1 to P4 are to check the lockout board. This model doesn't have 220 vac at infinite switch all the time.

[ECtoFix]

@Vance R

Gotcha.  I hadn't yet accessed to a schematic to refer to when I chimed in.  Also, I misunderstood what results he got from his test points.

I looked at the schematic and read up on the cooktop lockout feature.  Interesting setup. 

 

[cpjxh7]

Will check to tomorrow and post back. We've had issues with the cooktop lockout in the past, starting on day 1, when it was under warranty. 

Is testing L1 to P2  just bypassing the cooktop lockout board. And L1 to P4 including the cooktop lockout board but bypassing the surface unit switch? To see where it is failing?

What is the best way to test to P2 and P4 on the cooktop lockout board, assuming I can't fit a probe into the connector when it is plunged into the board. Thanks so much!

[Vance R]

This is just to confirm L2  into the lockout board and if it is coming out of lockout board.  Looks like the control signal for the lockout board is on P1, but this just a guess because there is no information on how the board works. If you feel safe jumping P2 to P4 would bypass the lockout board to confirm the operation of infinite switch and element.

[ECtoFix]

Here I go chiming in again…

So, the focus now is on the lockout board. Right?

I know you said you swapped the lockout board with a spare, but how do you know the SPARE is good?

If the “cooktop lockout” feature is NOT turned on, then all the relays on that board should be de-energized, so all of that board's relay contacts should be CLOSED (they're normally closed per the schematic).  Therefore, ALL cooktop controls should be getting voltage from L2 and be working. RIGHT?

ALL except this one element circuit ISN’T.

What I’m suggesting is maybe the relay for that particular element might have bad contacts.  Your voltage tests seem to indicate that leg (L2) is non-existent at the infinite control.

So, why not unplug power from the range, unplug either wire to P2 or P4 (to isolate) and just test across P2 and P4 with your ohmmeter?

• If it reads OL (on a digital meter) or ∞ (on an analog meter), then the contacts are testing OPEN, so they’re bad and you need a new lockout board (pn 316418100).

• If it reads nearly 0Ω, then there's the unlikely scenario that the relay is probably good and then you’d be concerned as to whether the main control board is errantly signaling for that ONE relay to open.

FWIW: I understand folks wanting to jumper things out, but I have r-a-r-e-l-y practiced that in my forty years of troubleshooting.  YES, I think I did it ONCE this year, but my meter serves as my eyes to see what’s REALLY going on.

I’ll also add that the itsy-bitsy contacts in those little relays on circuit boards are prone to failure.  I think you said your element resistance was around 40Ω?  Ohm’s Law calculates to 6A of current through those contacts rated for 10A.  The element’s nearly constant resistive load through those tiny contacts can quickly take a toll if even a speck of dust settles in between them.

[Vance R]

1 hour ago, ECtoFix said:

So, the focus now is on the lockout board. Right?

Yup, think this a good possibility at the moment.

 

[ECtoFix]

@cpjxh7

Like a fly in the room, I’m BACK!  LOL!

Bear with me as I’m a commercial cooking appliance tech, not residential – but I’m always curious about what challenges my counterparts repair on household appliances.  With the amount of details you offered in your posts, I kept coming back to look at it.

As I RE-re-read your initial post, something caught my eye:

Quote

I did check the thermal limiter on the burners. 1a to 2a and 1b to 2b are both OL when it is cool, which tests OK.

The schematic calls that a temperature limit switch.  I honestly didn’t know its physical location until I did some research on-line.  SO…it’s mounted to the element.

On the schematic, that component is shown to be NORMALLY CLOSED.  Yet, you said your test (with an ohmmeter) across terminals 1A & 2A read OL…and you called that “OK”.

Well, that’s NOT okay and is going to be a problem too.  

Here’s a video on testing not only the element, but the limiter as well:

How To Test Your Radiant Surface Element & Wire Limiter

Of course, this has nothing to do with your not getting 220v to L1 & L2 of your infinite switch.

Here's a copy of the schematic, although I don't know if it's readable here.  Here's a link so you can magnify it:  https://c.searspartsdirect.com/lis_png/PLDM/R0408106-00005.png?wid=150&hei=150&resMode=sharp

.

[Budget Appliance Repair]

18 hours ago, ECtoFix said:

On the schematic, that component is shown to be NORMALLY CLOSED.  Yet, you said your test (with an ohmmeter) across terminals 1A & 2A read OL…and you called that “OK”.

 

Well, that’s NOT okay and is going to be a problem too.  

YES, to the above - if 1A to 2A is open on any element when it is cold you will need to replace the complete element, (this is the Hi-Limit switch to shut the element down if it gets too hot - like with no pot on element).

1B to 2B should be open until the element heats up to a moderate temp to turn the hot surface indicator light on - element will still work if this contact fails open or closed, (Most common is to fail in a closed state so it shows as a hot surface all the time).

The hi-limit/hot surface sensor used to be replaceable a long time ago but are now part of the element and have to replace the complete element if you are having any problems with either hi-limit or hot surface switches.

[cpjxh7]

@ECtoFix I looked back in my notes and sorry, that is a typo on my part. Both 1a to 2a and 1b to 2b show continuity when the surface is cool. One thing to note is I did not isolate the the circuit when I tested them, I just tested across the  connectors on the element. Would this impact my tests and be why I had continuity between 1b and 2b? I am planning to do the testing recommended by Vance today and will post back tonight. Thanks again! FYI - the wife went stove shopping yesterday! She is loosing faith. LOL!

[cpjxh7]

Just to add, I did isolate 1a to 2a, but the wires on 1b to 2b are extremely difficult to pull off. Is there a trick to getting them off?

[Vance R]

The terminals should be all the same. Sometime you have to use small screwdriver on edge as a pry tool to get them started.

[cpjxh7]

Here are my updated test results.

Plugged Into wall outlet: all wires were left plugged in the infinite limit switch. 

• L1 to L2, ON = 16v, OFF = 18v
• H1 to H2, ON = 0v, Off = 0v
• Terminal Block, Red to Black = 267-283v, Red to White = 126v, Black to White = 126v
• L1 to P2 (CTLO board), OFF = 240v
• L1 to P4 (CTLO board), ON = 17v

Unplugged from wall outlet: all wires were left plugged in the infinite limit switch. 

• L2 to P4 (CTLO board) = continuity
• P to P1 (CTLO board) on the purple wire 2nd from the bottom = continuity 
• H1 to H2, ON = 45 ohms, OFF = 45 ohms --- so temperature limit switch is closed
• L1 to H1, ON = OL, OFF = OL--- so surface unit switch is open
• L2 to H2, ON = continuity, OFF = OL 

On the connector that has the 6 wires (P2, P3, P4, P5, P6, P7) that plugs into the CTLO Board, the area on the outside of the plastic connector is black by P3 and P4. 

Thanks Again!

[cpjxh7]

Just now, cpjxh7 said:

infinite limit switch

"infinite switch"

[Vance R]

Ok, looks like surface switch is not closing L1 to H1 you'll need and infinite switch.  Next part is a guess, it is possible that terminal P is not closing to L1 inside the infinite switch. This may keep the lockout board from closing the relay to complete the circuit to L2 for the element.

2 hours ago, cpjxh7 said:

the area on the outside of the plastic connector is black by P3 and P4. 

 Are you saying the connectors P3 and P4 are discolored as in burnt? If yes then these terminals would need to be replaced. If you do replace terminals make sure to use high temperature ones.

[cpjxh7]

Hey @Vance R If it's the switch, isn't it odd that  when I swapped the infinite switch back and forth between the left and right back burners both of the infinite switches work on the left back burner but not on the right back burner? Also, when I tested the infinite switch this is what I got.

OFF:

• L1 to P = OL
• L2 to H1 = OL
• L2 to H2 = OL

ON:

• L1 to P = continuity
• L2 to H1 = continuity
• L2 to H2 = continuity

9 minutes ago, Vance R said:

Are you saying the connectors P3 and P4 are discolored as in burnt? I did test L2 to P4 (CTLO board) and had continuity.

No, just the outside plastic connector that holds the 6 wires and snaps onto the board is black. I did also check L2 to P4 on the CTLO board and had continuity, assume this means the connector is not burnt and can still make contact. Not sure how to upload a picture.

Thanks!