First you should determine whether it's cooking when it should not be, in this case anytime it is plugged in and the door is closed or
Do that by putting a cup of water in a microwave-safe container into the unplugged microwave, shutting the door, then plugging it for about a minute.
Then unplug the oven and check to see if the water is warmer.
If so, you have a shorted secondary relay on your microwave''s control circuit board, and we regularly repair such control
customers nationwide by mail for $39.95 with a one-year guarantee.
Do that test again by putting the water in, leaving the door open, and
plugging the oven in for about 30 seconds or so. If you get any arcing
or buzzing or flashing, unplug it.
If it is not cooking, then you need to test further.
If it just seems to be "running" with the door shut, but it is not cooking (as shown in the above tests) then note whether the oven lamp, internal cooling fan and turntable are running when the door is shut, but when you open the door, the turntable and colling fan go off.
This should mean you have a shorted main relay on the board. We can fix that, too.
Differing symptoms would indicate a bad door switch or door switch mount.
Our info file on door switches is here.
should be a "mini-manual" (tech sheet) hidden inside the unit
control panel or hidden on the left side behind the grille, which is
very helpful when troubleshooting, testing, and locating
our Web site, we have a video
available showing how to remove a typical
over the range control panel assembly in under 5 minutes.
You can find
helpful exploded view diagrams and order parts by entering your full
model number here
We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.