I have a Frgidaire microwave model FMV156DCG just 3 years old. The very lowest door interlock switch (normally open & when door closed it closes the switch)) looks like it got hot and now won't work. I picked up a new switch but hesitant to replace it just yet. I jumpered across the two wires that go to the switch and microwave works fine but wires get hot after running microwave for just one minute. What would cause that? I'm afraid I'm going to melt another switch or maybe something worse. I traced the wires which go from one switch to another and to various components like fan, lights, turntable, magnatron, etc., nothing that I can see looks discolored from heat so not sure where to go from here. Any help would be apreciated ... thanks!

Yes, a bad door interlock switch would cause this; either the top switch or the bottom switch. (The middle switch is called the Monitor switch. If it were bad, you microwave would blow fuses as soon as you press Start.)

Pulled up a schematic on this will try and help the first pic looks as though you removed the secondary switch the bottom one if so that is the wrong switch it should be a normally open switch that one is normally closed this switch goes up top on the other side of the primary switch the one with 3 terminals, look at the second pic the switch with 3 terminals that red wire in the wrong spot the skinny orange goes there the switch I just told you to put up top the red goes to one terminal the white and brown middle form the 3 terminal goes to the other terminal, the blue/white and blue go to the bottom switch this is a normally open switch if you don't know how to read a switch look at the switch look at com follow the line to where it stops if it is NO=normally open, NC=normally closed your primary switch is in the right spot you want the switch next to it to be NC and the bottom switch NO it blew the 20 amp fuse once you correct the switches and wiring and put in a new fuse if you have no power then it blew past the fuse and burnt out the filter board happens some times about 60 bucks let me know if this helps

"There is some charring around one of the interlock switch terminals"

You have a bad connection. The connector and the switch it goes to should be replaced.

Our help file on door switches is here.

You can download GE owner's manuals and installation instructions here.

You can find helpful exploded view diagrams and order parts by entering your full model number from the tag on the oven here.

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If it stopped working while you were cooking my first guess is that the magnetron TCO got hot and opened. It is supposed to reset after cooling down, but if it is old it may not have done so. Of course, there should be at least two door switches that close when you close the door. There is also a monitor switch that closes when opening the door (open with door closed). If you remove the control you should be able to check continuity on all switches, but you need to remove the wires to get a true reading. Some M/O have a TCO on top of the cavity, but you need to remove the cover to get to that. If you need more help, just get back to me.

Check the door safety interlock switches.

Do you regularly shut the machine off by opening the door? Each event causes a small arc on the tiny contacts and will burn them. When they can no longer make contact, your microwave doesn't know if the door is open or closed. The machine must know the door is closed to turn in the magnatron (that thing that makes the heat).

Remove the cover and check the microw switches with a volt/omh meter.

Thanks for your interest in FixYa.com

The heat bulb is burned out you can look for the part at appliance parts pros . com to find your model and look to see if it is something you want to tackle. some are harder than others.

the fuses for microwaves are not normally placed on the control panel...they are in the back near the power cord...but the fact that it beeps 3 times means the fuse is ok...power is going in....most likely, the fault is one or more of the door interlock switches which arc every time you open and close the door and they corrode or wear down very badly sometimes even burn away so that there is no more contacts to come together....interlocks are cheap to buy and they just snap in place....access to them is easy...just remove the cover and look right behind where the door closes on the inside, you'll see a plastic bar on the door that when you close the door...it pushes on the interlock switches on the inside to activate the oven.......if the interlocks are ok...then you probably have a shorted magnetron....very common on any type of microwaves are these 2 parts...( the interlock switches and /or magnetrons.....it's not likely that your control panel is bad unless you physically see that something has burned on it.....good luck

silvio

The primary interlock switch on my Advantium has failed twice. The replacement part is available at: appliancepartspros.com part no. for my Advantium was AP2622452 and it cost $11.74 + $6.95 shipping.

For what it's worth, my nylon connector and wire covering were also scorched a bit but the last primary interlock switch lasted me for over a year.

Please note that I am not an expert at repairing appliances and that I assume no responsibility or liability for any attempt you may make to repair your own appliance.

This is usually an indication of a bad door interlock. Take resistance readings with the power turned off on the primary and secondary interlocks. You will need to remove the control panel to access them. There should be a wiring diagram somewhere inside the control panel to assist you in determining if the interlock is normally OPEN, or normally CLOSED. As you open and close the door the interlock should change states. Additionally, double all your connectors to make sure they are plugged in correctly. I had a similar problem once and it turned out to be a loose connection on one of the interlocks. I hope this helps you.