did you try to reset the float switch? If the float switch get the signal that the water is low it activate the pump wether it is plugged or not, it will continue to provide current to the plug where the pump should be plugged for about 3 minutes then it will do an auto shut off to prevent floading.
To reset the switch you must lift the little floater up and then back down.
That's all there is to it usualy.
I have 2 of them and they work well.
QUOTE (thatoneazn @ Sep 8 2010, 10:28 PM)

Hey guys,
I have had this A.T.O for about a year. Today it decided to not top off my tank. The water drops to the normal level( red light comes on for the sensor) and the yellow light comes on for the pump. My ehiem pump comes on right away, but not today. I disconnected it and pluged it independently and worked fine. Please help??? I only have it with one float switch at the time