Jenn-Air JMW3430 Microwave Combo Wall Oven - Not Heating

[Tomahawk]

Model Number

JMW3430WS02

Brand

Jenn-Air

Age

More than 10 years

My Jenn-Air JMW3430WS02 is no longer heating in the oven. I accessed the Diag page and there were no errors listed. I checked the Limit Switch and it was good. I verified that 220V was getting to the unit. I then went into the Component Activation page and was able to run the oven element / broiler element / low and high speed cooling fan options / and the convection fans and coils. All of these work fine in diagnostics mode but when I run the unit, it doesn't heat.

I checked the door switch and that seems ok. It seems like something is preventing it from turning on the elements during normal operation. Also, I think it's unrelated since it happened a week prior to this heating issue, but the cooling fan for the microwave magnetron no longer works. I plugged the fan alone into 120V and it runs fine - so it's not that. When I try to activate the relay for the cooling fan in the diagnostics page, it won't start the fan. Any ideas?

 

[Jake]

Usually when you are able to activate the components fine in diagnostics mode, but not in normal mode, then problem is the Appliance Manager. Make sure you disconnect power to your unit before replacing it.

Here's the Appliance Manager for your model:
WPW10292566 Electronic Control Board(Appliance Manager)

 

[Tomahawk]

Thanks for the fast reply Jake! Is there a way to confirm this before making this purchase? Is there a certain component that could be bad that I could replace - like a relay or some other discrete component on the board? Could this board also affect the issue with the cooling fan for the MW magnetron or would that be a problem with the MW Appliance Manager board - or something else? Also, is there a way to decode the logic signals sent to the boards on the RX/TX pins? THANKS!

 

[Jake]

I'm attaching your tech. data sheet below. Like I mentioned above, since the parts in question are working fine in diagnostics mode, but not regular mode, then its usually the software on the Appliance Manage has been corrupted.

Also, here is your service manual: https://drive.google.com/file/d/1iwZHxjrrV2XRlRivsVs_0E5N3AtVkaMC/view?usp=share_link

Could this board also affect the issue with the cooling fan for the MW magnetron or would that be a problem with the MW Appliance Manager board - or something else? Also, is there a way to decode the logic signals sent to the boards on the RX/TX pins?

It goes into much more detail about that in the service manual.

 

[Tomahawk]

Thanks Jake! I picked up a new Appliance Manager board for the oven today - but unfortunately that didn't help the issue. I sometimes notice when in Diag mode that the list of items in the Component Activation screen is either blank or doesn't contain all the items. If I power cycle the unit, that usually brings them all back. Does this point to the main console board being bad or could this be due to an issue with the Appliance Manager board for the microwave? The issue with the Magnetron fan still exists and I can't even get it to turn on in Diag mode.

At this point, after spending $300+ on the oven manager board I am not sure if the unit is worth spending another $200 on the MW Appliance Manager board or not. I certainly won't spend the $1500+ to replace the console board. I would replace the entire unit before spending that much. Do you think it makes sense to try replacing the MW board or move on to a new unit? Thanks!

 

[Jake]

I sometimes notice when in Diag mode that the list of items in the Component Activation screen is either blank or doesn't contain all the items. If I power cycle the unit, that usually brings them all back. Does this point to the main console board being bad

Ok, I didn't know that from your first post. That sounds like a console control board problem: Electronic Control Board WPW10344082

or could this be due to an issue with the Appliance Manager board for the microwave?

That I don't know, never ran into that issue before. The service manual would help you determine that.

You just mentioned this:

I then went into the Component Activation page and was able to run the oven element / broiler element / low and high speed cooling fan options / and the convection fans and coils. All of these work fine in diagnostics mode but when I run the unit, it doesn't heat.

And never mentioned:

Component Activation screen is either blank or doesn't contain all the items.

Or I would of had you check the console control board first.

So if the service manual is not helping, then its best to have a Jenn-Air tech come out and see what's going on. Or buy a new unit.

Its very unusual to have multiple problems like this at once unless you had a power surge or power spike after a blackout/brownout in your area recently.