Unit with Door Open

I have an AEG KM8403101m Micromat combi oven. During cleaning last week the door switch got locked in the closed position (even though the door wasn’t closed at the time).

The microwave now shorts out as soon as it is switched on.

I assume this is a safety feature (though I may be wrong).

Is there a way to reset to door catch? It seems pretty much locked in position and no amount of prodding through the small hole at the front will get it to move.

The door has two insulting hoop like protrusions that go in the pictured hole. I think the mechanism inside to door swings the catches down when it shuts to lock the door in place.

Close-Up Interior of Lock

  • Take a picture of the door latch, will tell us more how it works
    – asinine
    Mar 27 at 18:50
  • How old is the oven? My 9-year-old microwave oven had a latch problem a few days ago. I put it on the curb to be hauled away and should have the replacement soon. Beyond poking at it from the outside, I decided that due to the risk of a problem (currently it doesn't latch properly and while the controls work the oven will not turn "on", so 100% safe) and the age, not worth trying to tear apart and repair. But that's a $250 2.2 cu ft countertop. If your oven is more of a "built in", or of course if it is newer, then the equation may be a bit different. Key is whether you can get parts. So: * Ho Mar 27 at 18:52
  • it might help youtu.be/zaFP8JrgUlc
    – asinine
    Mar 27 at 19:20
  • FWIW this is what the safety switch apparently looks like: fixpart.ie/en/product/view/0091485177?apl=2046973
    – Huesmann
    Mar 28 at 13:18
  • I was able to reset the door catches with a hook of wire. So the catches are now reset… unfortunately the microwave is still trpping the switch when the door is opened
    – James A
    Mar 29 at 16:27

2 Answers 2


Yeah, it's a safety feature to be absolutely sure the thing can't emit microwave radiation with the door open. The unit is directly grounded unless the latches are disengaged in the correct sequence. This either trips the breaker or blows the main unit fuse.

Unplug it and open it up to see whether something's broken or just out of position. Usually you can pull the control panel off to get access. You may need to remove the vent panel from the top edge first.

Without knowing what unit we're talking about I can't be more specific. You might revise to make that more clear.


This is your switch: enter image description here I believe it works when the loop on the door impacts against the part of the cam where my red arrow is pointing (think of the arrow as the door loop). The plastic hook on the cam rotates in the direction of the blue arrow, capturing the hook, and rotating the (yellow circled) bump on the cam to press the (green circled) button on the (white) switch.

What I suspect is that the cam has become stuck in the locked position. The switch itself may still be good, or it may be part of the reason the hook got locked in place. These little switches are easily replaceable, if you can find the right part (NC or NO, yours should be NO).

If it's just that the cam is stuck in place, maybe you can get it to release by using some kind of other loop-like tool and prying it up or down (not clear which orientation the switch is) with some leverage. In theory, you should be able to just pull the hook on the cam. enter image description here

  • This was incredibly helpful, thanks:). I’ve now reset the door latches, but it seems the microwave is still shorting when the door is opened :(
    – James A
    Mar 29 at 16:24
  • @JamesA Unfortunately microwaves are required to be tamper-resistant by law -- of the 3 (IIRC) door latch switches, one of them is required to blow an internal fuse if it's tampered with (if it's in the closed position with the door open and the microwave tries to start.) So my guess is that internal tamper fuse has blown. 21 CFR 1030.10 (c)(2)(vi) "A means of monitoring one or both of the required safety interlocks shall be provided which shall cause the oven to become inoperable and remain so until repaired if the required safety interlock(s) should fail to perform required functions..." Mar 30 at 3:42
  • If it's the fuse, you're likely looking at unmounting the unit and opening the case. Parts diagram here (electrical parts exploded diagram): ransomspares.co.uk/parts/brands/aeg/cookers-hobs/… seems to indicate a fuse holder (pic: fixpart.ie/en/product/view/0090161785?apl=2046973) at the upper left side of the unit. Appears to take this type of fuse (volts and amps may vary): m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/…
    – Huesmann
    Mar 30 at 14:39
  • UPDATE: using the response below I used a wire hook to reset the latches about a week ago, but the microwave kept shorting. Having come back from a week’s break it now appears to be working perfectly… maybe it has reset itself somehow?
    – James A
    Apr 7 at 9:13
  • Well, as long as it's working, just keep monitoring. Can you explain what you mean by "shorting?"
    – Huesmann
    Apr 7 at 12:13

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