A few years ago our Admiral agd4475tq1 gas dryer would no longer heat when the 'Auto Sense Dry' setting was selected. It would still heat using any of the 'Timed Dry' settings though so that is what we have been using since that time. At that time I replaced the thermal fuse (which was ok) and I tested the Dryer Cycling Thermostat on a stove top and it worked fine.

Now a few years later, the heat will only come on when the knob on the timer is set to 10 minutes or less in the 'Timed Dry high heat' section. Then once the heat is on I can move the timer knob to the 20 minute mark and it will keep heating. If I move it above the 20 minute mark (max is 30) the heat will shut off. The timer knob will count down and the the dyer will shut off once it reaches zero. If I keep moving the knob between the 10 minute mark and the 20 minute mark the dryer will keep on heating for hours.

So I am thinking the problem with the dryer is most likely the timer?