Maytag dryer won't stop on timed dry

Hi,

On our Maytag LDG712 dryer, the timed dry operation doesn’t stop the dryer. I set the timer to 10 minutes, the timer advances to the zero mark (top of the dial), but the dryer doesn’t stop. It continued for over 20 minutes before I opened the door to stop it. I had replaced the timer with a refurbished timer, but this didn’t solve the problem.

Is there some other mechanism which should turn off the dryer? Any thoughts on what might be going on?

Thanks, John