Why won’t the microwave start?

I don't know how handy you are around electrical appliances, but just about every single time my microwave has quit working on me it's been because of the @#$%^ door switches. For some reason those things seem to fail all the time. The good news is they're usually fairly easy to replace, and not expensive.

Unplug your microwave and open it up. You're looking for switches that usually look something like this.

Once you've located them (there are usually more than one; most of mine have had three or so), note the location of the wires going to them and unplug them. Connect an ohmmeter or continuity tester to the terminals and verify whether the state changes or not when the door is opened and closed for each switch. If one fails to change, there's a good chance that's your culprit.

When ordering replacements, pay attention to the voltage and current rating, as well as the location and number of terminals. Some of them will have two terminals for NO (normally open) or NC (normally closed) operations, and others may have three terminals for both.

If you get a three-terminal switch, you can use it in place of either an NO or NC switch; you just have to make sure you connect to the terminal that corresponds to which function you want, NO or NC.