This occurs when set on Hi. The seat will heat up and cycle on and off. IF i am not mistaken, the owners manuel says to start on high and when the seat reaches desired temperature to switch it to low, since when at low, it will maintain the current temp. Please don't take my response out of context, I had the same question when I picked mine up this year, and yes it took much digging through the encyclopedia that came with it to find the needed info.