Kenmore Dryer cuts off and on does not dry Clothes as it should

My dryer starts the light moisture light comes on and then it cuts off in about 5 minutes of drying. It will not stay on. I can wait about 30 mins. or more and try again and it will not stay on to dry the clothes. I have checked all vents, etc. Nothing is obstructing the vent. I wanted to know if you think I need just a new sensor to make it good as new again?