EW30MO55HS Electrolux 30"microwave doesn't turn or heat

Take it in for repair. Could be a micro-switch, but could be main board, or magnetron.

https://www.fixya.com/support/r29874712-repairing_microwave_ovens

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Accumulating steam is usually caused by the fan not operating or the vents are blocked.

I appreciate your post, friend!

Based off the information you have provided your Electrolux built in microwave is displaying an error code of "ECON". I am showing that this is an invalid error code. I would recommend you perform a reset on your microwave and you can do that by disconnecting the power cord for roughly ten minutes. If that does not help correct your issue I would suggest contacting a professional technician for proper diagnosis and repair. This will help you avoid any unnecessary part purchases. -Matt

To diagnose i would check if the fan "always" turns on in the start of microwaving a meal? and or if it gets hot and then "always" turns off at a certain time?

if it always turns on and then turns off at a time such as 30 seconds, probably getting hot and over heating - replace fan motor

if it turns on for the first meal but then is off or on intermittenly probably a switch or wiring is loose.

That would be a failing bottom door switch, or its mount.
My help file on door switches is here:
http://031d26d.namesecurehost.com/mwd/doorsw.txt
There's a video here showing how to remove a typical over the range control panel assembly in under 5 minutes.

Once the control panel has been removed, you can access the door switches for testing and possible replacement.
There should be a technical manual hidden behind the controller or grille, too.
If you need further part ordering help, contact Electrolux:
USA
800•944•9044
Electrolux Home Products
North America
P.O. Box 212378
Augusta, GA 30917

Canada
866•213•9397 (English)
866•294•9911 (French)
Electrolux Home Products
North America
6150 McLaughlin Road
Mississauga, Ontario, Canada
L5R 4C2

If the unit operates correctly except heating the food, then the unit needs a new magnetron.

There are three common issues, magnetron "heats food" cracked high voltage diode, or a shorted high voltage capacitor. In order to find out you will need a professional to assess, it will be probably cheaper to replace the microwave oven.

It is good that the microwave does not work all together. It might be an interlock button or even a relay connection burn on the main mother circuit board.

Need a qualified technician. The service manual will be like $20-50.

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sounds like the magnetron is dead, cheaper to replace the microwave than get that part replaced unfortunately... unless you can find another of the same model (or compatible) for parts.