Dryer runs but wont auto shut off

possible blockage in vent if ok bad fan motor or heating element overheating

It’s most likely caused by your Cycling Thermostat AP6007567. When this thermostat opens due to heat in the blower housing, the timer starts running. I believe this thermostat is bypassed in the Timed Dry mode. The thermostat is on the blower housing so you would have take the front off the dryer to access it.

In some dryer's the control panel relies on a thermistor rather than a CYCLING thermostat to regulate the drum's air temperature by monitoring the component's resistance changes; resistance goes down as temperature increases and up when temperature decreases. Once the drum's air temperature reaches a certain level required to dry clothes, the control panel shuts off the heater. The panel will turn the heater on again and begin another heating cycle when the thermistor indicates that more heat is needed to keep the air temperature constant inside the drum

Lastly check your moister sensor. ( located inside the dryer door usually) Especially if machine seems to shut down early and clothes are still wet.
Test with a meter at room temperature and it should show continuity.
A failed moisture sensor will affect the dryer run time in the automatic moisture sensing cycle but it will not affect the heating of the dryer or the timed cycle. Which are reflected by the thermostats.

Read more :http://www.ehow.com/info_12203962_check-dryer-thermistor.html

A timed drying cycle uses the timer alone to stop the drying cycle. Once it times out like an egg timer a set of contacts open up shutting off the dryer. Or a set of contacts closes to activate a relay which in turn shuts off the power.
Auto dry usually uses a moisture sensor which would do the same thing as the timer. Once it doesnt sense moisture in the load for a predetermined time it in turn triggers a relay which shuts the power off. Some auto dry cycles just use the timer alone and guess-timate the drying time by the selection.
If yours does not use a moisture sensor then most likely it is your timer/cycle switch. There may or may not be a relay involved.
Most dryers have a basic wiring diagram on the inside somewhere on one of the panels which will help.
Since yours is acting up on both cycles Im guessing you have a bad relay or connection to that relay somewhere IF it uses a moisture sensor.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/john_32f4b76dad4781c4

You probably need the timer replaced.

Check to see if the unit will heat up in the time dry. if the heater does not come on in the time dry cycle, then you will need to change the thermol fuse on the back of hte dryer.

You may not be getting sufficient air flow--remove the lint filter and wash it with detergent and hot water. Also clean excessive lint out of the air vents (under the filter too). Don't use 'perm press' if you want things absolutely dry. Remove and hang up before they cool. 'Damp dry' really means 'don't dry' I guess!

auto dry relies on a moisture sensor to say when its done. so your clothes arent dry enough according to sensor. perm. press. doesnt dry the clothes as much

https://www.repairclinic.com/Shop-For-Parts/a8b104d87061/Model-CYE2000AYW-Magic-Chef-Dryer-Parts

The dryer requires cycling of the heat to advance thhe timer on auto dry cycle. see ,link provided parts and repair guidance. Always remove from power supply first.

I’m happy to assist further over the phone at https://www.6ya.com/expert/david_dc2f9e0a44104720

Our Kenmore dryer had the same sort of problem (different catchy names.

Problem was that in "smart" modes (by what ever name, the timer motor runs in series with a "dampness" sensor (thermostat, actually, I think) and A RESISTOR.

Resistor burns out--this is the symptom set.