My kenmore dryer heat element goes on and off. The clothes take hours to dry.

It seems to run forever If your dryer seems to run forever, it could be because of a clogged vent or internal ductwork. Your dryer may have an automatic cycle that turns off the dryer when the clothes are dry. It does this with a special thermostat or moisture-sensing system. Normally, this is what happens during an automatic cycle: The thermostat tells the dryer to heat until the interior of the dryer reaches a pre-set temperature--say 135 degrees. When the dryer reaches the pre-set temperature, the thermostat tells the timer to begin advancing. (If there's a moisture sensor, the timer advances only if the moisture content of the clothing is low enough.) The timer advances until the interior cools, then the thermostat tells the timer to stop advancing, and tells the dryer to start heating again. This cycle continues until the clothes are dry. But…if the vent is clogged, the dryer may never reach the proper operating temperature, so it doesn't send the signal to the timer and the dryer continues to run indefinitely, even if the clothes are completely dry. To fix the problem, clean the vent and/or internal ductwork.