[jennarnott]

The dryer will not shut off in automatic dry cycle. The heat works, so it is drying the clothes but it continues running long after they are dry.

The duct is clear, the lint trap is clean.

One person told me it could be a humidistat, another told me it was a moisture sensor issue. I still don't know how to fix it! I'd hate to scrap the whole dryer if it is something easily fixed.

[denman]

Here are your parts
Replacement parts for Amana ALE643RAW DRYER- ELE | AppliancePartsPros.com

Since you specifically mentioned auto cycles I am asuming that the unit does shut off in timed dry.

I could not find a wiring diagram for this unit but can say.
The unit does not have a humidistat.
I also could not find a moisture sensor or it's control board in the parts and no mention of one in the operators manual.
If it does have one it will be two metal strips mounted on plastic inside the drum area or on the back of the drum.

If I assume that it does not have a sensor then the way auto works is that the timer motor gets power through the heating element when the heater is shut off.
Unplug the unit and both wires at the heating element.
Measure across the element, usually around 8 to 12 ohms.
Also measure from each side of the heater to the frame. Both should be infinite ohms.
If not the element is grounded and should be replaced.