Clothes dryer won't shut off

Just like the subject reads, my clothes dryer won't shut off. It dries clothes in the expected length of time, but it just keeps running through all of it's cycles. I have to open the door or unplug it to stop it. When the same thing happened about 6 months ago I opened a couple of the panels and vaccuumed out all the lint and crap, put it back together, and the problem disappeared. The local appliance parts store thinks I need a new timer - $85. But before I replace the timer on a hunch, I wanted to solicit advice from others in this group for other possible causes - specifically components that I can check or measure, or a method to diagnose the cause so I would have a better certainty that the timer is indeed the problem
It's a Sears Kenmore model/stock no. 97589210 75892; serial no. ME4409635 purchased in 1995. Natural gas. Lint trap cleaned with each use, and the vent is free flowing. It's been a great machine and I'd like to keep it going. TIA, M.Paul
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Check the vent tube and outlet flapper, might be clogged with lint. If the dryer isn't moving air, it will never quite dry the clothes, and the dryer will keep running.
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Christopher A. Young
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