The part(s) or condition(s) listed below for the symptom Garbage disposer stopper switch won't turn on disposer are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
Some garbage disposer models have a stopper switch (or batchfeed stopper). The batchfeed stopper activates the start switch to start the disposer. If the start switch is defective, the disposer will not turn on. To determine if the start switch is defective, use a multimeter to test the start switch for continuity. If the start switch does not have continuity, replace it.
The wall switch might be defective. Use a multimeter to test the wall switch for continuity.
If the garbage disposer stopper switch won’t turn on the disposer, the batchfeed stopper might be defective.