I had exactly problem and took the same steps to fix...called electrician and the problem was in the switch on the wall...it was partially working but not sending enough "juice" to the disposal....just enough to make a humming sound. The wall switch was replaced and it work great now.. ... View related article.
Have you tried powered dishwasher soap and hot water? Let it soak in the washer for a few hours and then check. If need be, soak longer,, or repeat the process. This works for me. Mar ... View related article.
