Symptom was that my Whirlpool dryer would run, but without heat. Dryer duct work was clear, and drum spinning would indicate 220v isn't the problem. Skipped testing the timer, and began to test heat related components with an ohm meter. Heating element, themostats, and fuse were good, but the cut-off was the culprit. Choice - repair a 21 year old dryer with a $25 part, or replace the unit? Went the route to repair the dryer after looking at prices of new units. Replacing the thermal cut-off was a quick fix ... back to doing loads of laundry - is that a good thing?
Note: While the heating element tested good with an ohm meter, performed a visual inspection. With the rear panel removed, I also had to remove the top panel. A sheet metal screw holds a clip for the element box at the top. Once the heater box is removed, remove the screw holding the element in the box. Remove the element for a visual inspection. Do not try to remove the element while the box is still attached to the dryer for this model (box is one piece and element is approx. 16" long).