I had the same problem and it turned out to be a clogged jet. If you have a 2 line system remove the lines from the pump. You will have to make a plug with an air chuck in it so you can pump some air into the system. The larger of the 2 lines will get the air chuck and the smaller should be directed into a bucket. Blow air into the air chuck with a compressor and backflush the water through the jet and out of the small line. When I did this I had to do it twice but I got an huge amount of dirt and small pebbles out of the line. This junk cloggs the jet and the pump will not build pressure to shut off the switch. Good luck.