This happens on occasion with our old Whirlpool dryer, so I'm familiar with the troubleshooting and repair methods. This time it was the thermal cut-off switch - an open circuit when tested with the multimeter. Ordered the replacement part from AppliancePartsPros.com, it arrived the next day (standard rate shipping), and took maybe five minutes to swap out parts. Replaced the back panel, reattached the exhaust duct, plugged it in. Heat! Just another day in our house.....