Step 1: Unplug the dryer
Step 2: Remove the front panel.
Step 3: What is inside?
Step 4: Get your meter.
Then I checked the next thermostat back, the high limit thermostat. That should be normally closed. So the meter should read that it has continuity. Mine checked out ok.
The next one back, is the thermal cutout switch. this is designed to stop all flow if the temp ever gets above 350 deg F in the heater box. Mine, as you can see in the third picture is bad. Im not sure why it overheated but it will be replaced.