It's the contacts in the front of the motor. You can pull the motor (easy to do) and clean the contacts, put some electric grease on them and you'll be fine. I've had to do this twice now because the first time I did it I didn't have diaelectric grease handy and they worked good for about 2 years before they acted up again. Since using the diaelectric grease I haven't had any problems. I live in a high humidity area with lots of sea salt in the mist which probably causes the contacts to corrode faster than normal. Lots of video on utube if you're uncertain about how to do it, but it's really easy and takes only an hour or 2. Good luck, Smokey