Kenmore Elite Dryer will not run for more than a second...have done lots of troublesh

Dryer Repair
1

Hello,

I have a Kenmore Elite Gas Dryer (110-70952990) that is on the fritz and will no longer start and stay running. This dryer does have Even Heat Control.

I’ll begin by stating that when the problem started, the first thing I did was check the tube out the back of the dryer. It was packed full of lint so I vacuumed it all out. Dryer still wont run.

I’ll try to describe the behavior of the dryer the best I can.
I push the start button.
The dryer starts for a split second and the motor makes a horrible noise, the drum spins and then the machine stops.
I hear a couple of clicks
A few minutes later I hear another click
After about 5 minutes or so, the machine all on its own will try to start…the dryer turns on for a second and I hear the same horrible noise from the motor and the drum spins for a quick second.
This cycle of the dryer trying to start on its own will continue until the timer runs out.
If I try to start the dryer myself by pushing the button before all the clicking and 5 minutes goes by, the dryer is dead and unresponsive to me pushing the button. If I wait, it will try to start and run

So I took apart the dryer and here’s what I’ve tested and done so far:
Thermal fuse passed continuity test
Start switch passed the continuity test
Belt switch passed the continuity test
Door switch passed the continuity test
Blower wheel spins freely and there are no blockages
Checked for voltage at the Timer
Checked for voltage at the start switch and motor relay
One of the two drum rollers on the back wall didn’t spin too freely. I cleaned and lubed it. Spins better now.
Drive belt is intact and seems fine
Drive belt idler pulley is intact and lever seems fine

According to the parts website, if all these parts are good, then the motor is probably bad. I was just about to order a motor, but wasn’t 100% convinced. So, I took out the motor, put it on my workbench, applied power, triggered pin 5 to start it, and low and behold it started and ran beautifully! Nice quiet hum and ran indefinitely. So now I’m thinking the motor isn’t bad, but part of me wants to reinstall the motor and do the same test to see if the motor sounds or acts differently when there is a load on it (belt and drum installed with some clothes in it)

If I’m understanding my situation correctly, the parts website makes no mention of the the Even Heat Control board being the culprit for this particular problem, but the Troubleshooting guide I found inside the Dryer says that if all the parts test out good, then the Even Heat Control board is to blame and not the motor since it does technically start.

So where do I go from here? What else can and should I test?
How can I test the Even Heat Control board to be sure it’s bad?

Thanks in advance for your help
James

2

The motor should start and run as long as you hold the start button down regardless if there is a problem with the control board. If it won’t start and run while holding the start button, we need to determine where you are losing power.

Continuity tests are static tests and can tell you if a part is bad, they don’t necessarily tell you if a part is good. This is due to the fact that your multimeter is only using a very low voltage and current to test resistance but in actual operation, the machine is operating on 120vac and drawing several amps of current. What that means is that a set of contacts can read good with a simple continuity test even though the contacts may be faulty and will break down under actual load conditions. The better way to test is using the voltage drop method. Monitor the voltage to ground at the timer BU terminal while pressing the start button with timer on. Voltage at BU should be around 120vac and remain close to that even when start switch is pressed. If the voltage drops significantly, then the timer may be bad. You would need to do the same test at timer BK terminal to confirm. If timer appears ok, do the same test at the COM terminal on the motor relay to determine if the relay is ok. If good, same test at belt switch. If your not dropping voltage across any of these devices (timer, motor relay, belt switch), then we need to check the neutral circuit.

Eric

3

Eric, thank you for the detailed and easy to understand response and great suggestions.

I will have the time to do this tomorrow night and will report back my findings on Friday.

Thanks again.

4

Eric,

As another test, is it safe for me to bypass the motor relay all together and simply connect the wires?

5

You are bypassing the relay when you operate the start switch. The start switch and relay are in parallel. You activate the start switch which should start the motor and signal the control board to activate the relay so that when you release the start switch, it continues to run. But yes, you can rule out the start switch as the problem by jumping the two wires together. Make sure timer is off first so there is no voltage to the wires. Then you can either jump the two blue wires from the motor relay or the two black wires from the start switch. Turn timer on and motor should start. If not, continue with the voltage drop tests.

Eric

6

[QUOTE=fairbank56;869266]The motor should start and run as long as you hold the start button down regardless if there is a problem with the control board. If it won’t start and run while holding the start button, we need to determine where you are losing power.

Continuity tests are static tests and can tell you if a part is bad, they don’t necessarily tell you if a part is good. This is due to the fact that your multimeter is only using a very low voltage and current to test resistance but in actual operation, the machine is operating on 120vac and drawing several amps of current. What that means is that a set of contacts can read good with a simple continuity test even though the contacts may be faulty and will break down under actual load conditions. The better way to test is using the voltage drop method. Monitor the voltage to ground at the timer BU terminal while pressing the start button with timer on. Voltage at BU should be around 120vac and remain close to that even when start switch is pressed. If the voltage drops significantly, then the timer may be bad. You would need to do the same test at timer BK terminal to confirm. If timer appears ok, do the same test at the COM terminal on the motor relay to determine if the relay is ok. If good, same test at belt switch. If your not dropping voltage across any of these devices (timer, motor relay, belt switch), then we need to check the neutral circuit.

Eric[/QUOTE]

I am working on a Kenmore gas dryer model number 87994100 that will not start. It has a touch pad type of control panel . There are 3 switches on the back side of the door—2 of these are push button and one is a lever type. If I open the door and hold both of the push button type switches in to simulate the closed door the drum attempts to turn but stops very quickly, I cant find a schematic and also cannot find the p/ns of these switches. Can anyone help me and also show me where I can get the switches in this dryer ?

7

Hi Eric,
I have some new information

For both the BK and BU on the timer, I saw a voltage drop. It read 118.8v and dropped to 107.2v after I pushed the start button. This was with reference to ground. When I did the same test with reference to neutral, it went from 118.8v to 106.5v

Regarding the motor relay, there was no volt reading on the common wire as you suggested so I was unable to do a voltage drop test. I did determine though that after the push button is pushed, that the common wire shows 120v and holds 120v for 3 minutes until I hear and feel a click at the harness that plugs into the motor. After the 3 minutes, the volts drops back to 0.

The same thing happens with the push start switch. There is 120v coming in and 0 volts going out initially. Once I push the button, the circuit closes and 120volts passes through the switch just fine and is held for 3 minutes as well. After 3 minutes passes, the switch returns to being open.

Going back to the motor relay, and testing the normally open (NO) blue wire, I was able to monitor a voltage drop and saw it go from 118.8v to 106.2v once the start button is pushed.

For the belt switch, both terminals showed it go from 0v to 118v (and held 118v for 3 minutes) once I pushed the start button.

I re-installed the motor for the heck of it and kept the drum out, pulled the spring on the idler pulley arm and taped the arm out of the way so it wouldn’t interfere with the belt switch continuity. No change, so my hunch of the motor possibly running w/o a load on it has been proven false.

On a side note, my cheapo Harbor Freight DVOM was able to perform these tests, and same with my middle of the road Craftsman DVOM. But my new Fluke 87V DVOM wouldn’t pick up the voltage and always showed “OL”. Do you know why this is? I really wanted to use the Fluke because it has the ability to capture the min and Max values, rather than me just watching the screen.

Does this new information mean anything to you? Any more advice or suggestions would be most appreciated.

Thanks for your help and time.
James

8

Well, as usual, trying to do electrical troubleshooting over a forum with a rookie is an exercise in frustration. Sorry, not your fault. I would suggest making a cheater cord out of an old extension cord and connect it directly to the motor to see if it will work. This will quickly rule out the motor as the problem. Connect hot to motor receptacle pin 4 and neutral to pin 5. Does the motor work? Your fluke is reading OL because you either have it on the wrong scale or wrong function.

Eric

9

[QUOTE=thorning;869422]I am working on a Kenmore gas dryer model number 87994100 that will not start. It has a touch pad type of control panel . There are 3 switches on the back side of the door—2 of these are push button and one is a lever type. If I open the door and hold both of the push button type switches in to simulate the closed door the drum attempts to turn but stops very quickly, I cant find a schematic and also cannot find the p/ns of these switches. Can anyone help me and also show me where I can get the switches in this dryer ?[/QUOTE]

The Kenmore dryer was switched out to another type and brand yesterday–an older model Whirlpool with a rotary timer. After I got the Kenmore unit back home I plugged it in to the 110 volt outlet and hit the start area of the touch pad panel and it did not work. Thinking I was going to have to scrap it I walked away to get a tool and came back and tried it again. Praise the Lord it turned on and runs well !!! As I suspected however the door lever type switch is the culprit and Sears told me to forget about getting a replacement. A couple of bumps on the door and it would start but not everytime. I am going to go to an appliance scrap dealer and see if they have this type of switch. If anyone out there has the lever type door switch for this model Kenmore gas dryer 110.87994100

In my description of the switches I mentioned that this dryer has 2 pushbutton and one lever type switch for the door. In actual fact the lever type switch is actually a push button actuated by a spring plate. I am still looking for an exact new replacement for this switch as the one set of contacts/terminals are blackened which indicates to me that it is damaged internally. In the meantime I found an old pushbutton type switch I installed to do the function of this switch. It is a single pole type and appears to work for this function. I will report back later to see if it does indeed work OK.
If anyone else has ever noted this blackening of the terminals(and presumably the internal contacts) of these type of pushbutton switch I would like to know. I have noted it on rotary timer dryer switches I have dismantled. Any help in respect to this problem area is appreciated.

10

[QUOTE=fairbank56;869621]Well, as usual, trying to do electrical troubleshooting over a forum with a rookie is an exercise in frustration. Sorry, not your fault. I would suggest making a cheater cord out of an old extension cord and connect it directly to the motor to see if it will work. This will quickly rule out the motor as the problem. Connect hot to motor receptacle pin 4 and neutral to pin 5. Does the motor work? Your fluke is reading OL because you either have it on the wrong scale or wrong function.

Eric[/QUOTE]

Hi Eric,
What I describe in my very first post on how I tested the motor on the workbench is in reference to the following this video:
Dryer Troubleshooting - Start and Motor Switch Testing - YouTube

Your way seems to be a bit different. Does it matter?

Also, with the information I recently provided, are those acceptable voltage drops or unacceptable voltage drops?

I also wasn’t able to test the motor relay exactly how you asked. What do you think about my test results the way I tested it?

What about the strange 3 minute behavior I described? Mean anything?
Thank you.

11

The guy in the video doesn’t know what he is talking about. He has it hooked up wrong and his explanation as to how it works is wrong. Yes, it will work the way he is connecting things but it is ass-backwards. The way he has it wired, when the motor starts, power to the run winding is through the centrifugal switch. That’s not how it normally runs. The centrifugal switch is only for the start winding. There is no need to use a start switch to test the motor. Just connect power between terminals 4 and 5. The motor should start and run normally as soon as you plug it in. The terminals are not 1-7 left to right as he indicates. From left to right, it’s 2-6-4-3-5-7-1. 1 and 2 are not used on your dryer, 7 is ground.

Your readings aren’t making much sense to me. I’m not going any further with trying to explain electrical troubleshooting. You have the tech sheet. The motor circuit is pretty simple. Power is via timer BK to BU, motor relay NO to COM, belt switch and door switch.

As for the 3 minute thing. Does it do that even if set to air fluff (no heat) setting?

Eric

12

[quote=fairbank56;869742]The guy in the video doesn’t know what he is talking about. He has it hooked up wrong and his explanation as to how it works is wrong. Yes, it will work the way he is connecting things but it is ass-backwards. The way he has it wired, when the motor starts, power to the run winding is through the centrifugal switch. That’s not how it normally runs. The centrifugal switch is only for the start winding. There is no need to use a start switch to test the motor. Just connect power between terminals 4 and 5. The motor should start and run normally as soon as you plug it in. The terminals are not 1-7 left to right as he indicates. From left to right, it’s 2-6-4-3-5-7-1. 1 and 2 are not used on your dryer, 7 is ground.

Your readings aren’t making much sense to me. I’m not going any further with trying to explain electrical troubleshooting. You have the tech sheet. The motor circuit is pretty simple. Power is via timer BK to BU, motor relay NO to COM, belt switch and door switch.

As for the 3 minute thing. Does it do that even if set to air fluff (no heat) setting?

Eric[/quote]

Eric,
I hooked up the motor via your suggestion of just the correct terminals 4 and 5. Starts and run just fine.

As for the 3 minute thing, yes it does this if set to air fluff.

13

I do have some other new information to share.

I also checked for resistance between pins 4 and 5 and measured 2.0 ohms, just a tad bit lower than the recommended 2.4 to 3.6 shown in the tech sheet.
I checked for resistance between pins 4 and 3 and measured 2.0 ohms, just a tad bit lower than the recommended 2.4 to 3.8 shown in the tech sheet.
I checked for resistance between pins 4 and 6 (and pushed the centrifugal switch) and measured 2.6 ohms, which falls within the recommended 2.4 to 3.8 shown in the tech sheet.
It’s my understanding that when motors fail the resistance is really really high, like 80 ohms for example.

I also performed the Factory Test. It passed all tests, except when I turned the timer to OFF. It then instantly booted me out of test mode and didn’t beep like all the other functions did.

I also performed the Timer Test and checked for continuity based on the Timer Encoding Table.
It passed all tests except the following 3:
It failed the BU to BK set to OFF and Timed Dry Mode Mode
It failed the V to BK set to Wrinkle Guard and Auto Moisture Sensing Plus Mode
It failed the BU to BK set to OFF and Auto Moisture Sensing Plus Mode

I’m thinking it’s the Timer or the Even Heat Control board now, and not the motor.

Any thoughts on my new info? Any help or input is appreciated.
Thanks again.
James

14

The motor winding resistances read low because you are measuring them in parallel. You must activate the centrifugal switch and then check each winding. 4 to 5 for the run winding and 4 to 3 for the start winding. Motor windings RARELY fail but when they do, they generally read lower resistance due to short circuit between the coiled wires when the insulating varnish on the wire breaks down.

Disconnect and jump out the two blue wires on the motor relay. If problem still exists, it’s not the control board. Try replacing the timer.

Eric

15

I’ll try your suggestions and report back. Thanks for sticking with me and offering advice. :slight_smile:

16

[QUOTE=fairbank56;870126]The motor winding resistances read low because you are measuring them in parallel. You must activate the centrifugal switch and then check each winding. 4 to 5 for the run winding and 4 to 3 for the start winding. Motor windings RARELY fail but when they do, they generally read lower resistance due to short circuit between the coiled wires when the insulating varnish on the wire breaks down.

Disconnect and jump out the two blue wires on the motor relay. If problem still exists, it’s not the control board. Try replacing the timer.

Eric[/QUOTE]

Hi Eric,

Ok. I believe I tested things properly now with the centrifugal switch engaged (pushed in) for all readings. Here’s the new results.

I checked for resistance between pins 4 and 5 and measured 3.6 ohms, which falls within the recommended 2.4 to 3.6 shown in the tech sheet.
I checked for resistance between pins 4 and 3 and measured 3.8 ohms, which falls within the recommended 2.4 to 3.8 shown in the tech sheet.

And could you please clarify as to what you mean by “jump out the two blue wires…”? Did I happen to do what you’re asking in one of my 5 tests below?

Here’s some new info and tests I did regarding the motor relay. Some of it makes no sense to me…

  1. I disconnected the two blue wires from the motor relay and hooked them together. Once I plug in the dryer, it attempts to start on it’s own as I’ve described in the first post (no need to press start button).

  2. I disconnected the two blue wires and the two pinks wires from the motor relay and hooked them together (blue to blue, and pink to pink). Once I plug in the dryer, it attempts to start on it’s own as I’ve described in the first post (no need to press start button).

  3. With blue wires disconnected from relay and the terminals jumped at the relay, it attempts to start on it’s own as I’ve described in the first post when I press start button

  4. With blue wires disconnected from relay and not connected to anything, it attempts to start on it’s own as I’ve described in the first post when I press start button

  5. With blue wires and pink wires disconnected from relay and not connected to anything, it attempts to start on it’s own as I’ve described in the first post when I press start button

Does any of this help determine if the motor relay is good or bad?

Thank you!

17

The problem is not the relay. Jumping out the relay blue wires means disconnecting the wires and connecting them together which you did. You should absolutely not have connected the two relay pink wires together. You may have damaged the control board by doing that. You are basically shorting out the 48vdc control board power supply by doing that.

Eric

18

[QUOTE=fairbank56;870796]The problem is not the relay. Jumping out the relay blue wires means disconnecting the wires and connecting them together which you did. You should absolutely not have connected the two relay pink wires together. You may have damaged the control board by doing that. You are basically shorting out the 48vdc control board power supply by doing that.

Eric[/QUOTE]

Thanks Eric. So where do we go from here? Motor? Timer? or even heat control board?

19

As I said before: “Disconnect and jump out the two blue wires on the motor relay. If problem still exists, it’s not the control board. Try replacing the timer.”

You can bypass the timer as well as a test. Unplug dryer, with two blue wires disconnected from motor relay and connected together, unplug timer wires and connect the black wire to the blue wire (not the black and blue wires that go to the control board). Plug dryer back in, motor should start. If it doesn’t, it’s not the timer, not the motor relay, not the control board. I see that your not really getting this at all. Have you tried to see what we are doing here by looking at the wiring diagram?

Eric

20

[QUOTE=fairbank56;870812]As I said before: “Disconnect and jump out the two blue wires on the motor relay. If problem still exists, it’s not the control board. Try replacing the timer.”

You can bypass the timer as well as a test. Unplug dryer, with two blue wires disconnected from motor relay and connected together, unplug timer wires and connect the black wire to the blue wire (not the black and blue wires that go to the control board). Plug dryer back in, motor should start. If it doesn’t, it’s not the timer, not the motor relay, not the control board. I see that your not really getting this at all. Have you tried to see what we are doing here by looking at the wiring diagram?

Eric[/QUOTE]

Yeah, just when I think I’m getting it, I’m not…apparently. Thanks for sticking with me though and offering great troubleshooting advice, I do appreciate it. I’m a Transportation Civil Engineer, and electrical work is not my strong suit.

Yes, I’ve been looking at the diagrams. My friend looked at it too (another Civil Engineer) and both of us agreed that it doesn’t make sense to activate the centrifugal switch for testing pins 4/5 or 4/3. But since we’re not appliance experts like you, we trust your advice and knowledge 110%. :slight_smile:

Ok. I will try your new advice regarding the timer. I hope it’s the timer as it’s the cheapest part of the probable suspects.