Product review (5 stars): Dryer tumbles but has no heat? This COULD fix it..
Came home from vacation, and ran too much in the dryer at once.  The big load kept the hot air from traveling through the dryer, and the heater coils got too hot. Modern dryers have cut-off thermal switches and fuses to shut the heat off and prevent a fire.

I looked up my model on-line, and found the 2 cut-offs that are attached to the heater. I actually ordered both, since it's a pain to open up some dryers, and for a few extra bucks, it's worth it.

It took me 2+ hours to change them out, but that is because my dryer requires the top/food/front/drum to be removed to reach the component.  Still cheaper than a service call!