This DIY dryer repair guide has step-by-step instructions about how to replace a mechanical timer on a dryer without keypad controls. A small motor on the back of the timer advances the timer and dial during the cycle, controlling the drying time. If the timer won't advance through the cycle, or if it doesn't start or shut off the motor or heating element, replace the timer with the manufacturer-approved dryer part.
The video below shows a gas dryer, but the repair procedure is the same. These basic repair steps work for replacing the timer in many Kenmore, Whirlpool, KitchenAid, Maytag, Frigidaire, Amana and GE dryers.