Maytag MDE6700AYW Electric Dryer Error Code "he"

The dryer seems to run fine but no heat. It also ran for several hours a couple times without drying the clothes. The manual says the code is for heating error. I checked the venting and it seems clear. I didn't go poking around a whole lot, but no indication of it being stopped up. So I am thinking I need a thermistor. Where is it located and is it something I can replace on my own? Any tips would be helpful. Thank you.