It's done this a few times before but now it's stuck in the on position. The only way to stop it is to unplug it. When I plug it back in, it starts running again without the stopper in place. I'm guessing there's something stuck that is activating the switch. Do I need to replace the switch or is there an actuator that needs cleaning or replacement.

Could not be fixed. Spent a bunch of time on the phone with maytag. Clearly they had a flaw in their switch design/part and basically refused to send me the replacement part because I might injure myself as a result of the repair. The best they could give me was something like 10 dollars off a future purchase. We decided we could live without a disposal. Very frustrating.... poor quality part, poor customer service