Kenmore dishwasher 665.17033401 doesn't heat?

My Kenmore dishwasher runs through a cycle OK, but then the Clean light keeps flashing. I have to reset it each time doing normal, heated dry, normal, heated dry. That turns off the light and I can run a cycle, but the heater element doesn't seem to heat the water. It never gets very hot and the dishes aren't getting clean. It's like there is scum all over them. However, the heater element tests OK. Any suggestion as to what the problem could be other than the heater element itself?