Auto dry is a feature of drying where you select how much moisture you want in your laundry...It works like this: There is an electronic thermometer in the exhaust of your dryer, measuring how hot the exhaust is, another one is measuring the temperature of the hot air before it goes into the clothes drum. An electronic circuit compares the difference between the two. Early in the cycle when the clothes are very wet, the evaporating water cools the air going through the drum to the exhaust, so the difference between the two temperatures are great. As the clothes dry, there is less water to cool the exhaust so the temperature difference between the two decreases, and thus can be looked upon as a measure how much water is left in the clothing. When you set the dryer for more dry, the dryer turns off when the difference between the two temperatures reach a set ratio that is narrower than if the dryer is set for less dry.