The most common cause for a dryers failure to start is a defective door switch. Door switches take a real beating with the opening and closing of the dryer door. The door switch is a normally open switch that closes when the door is closed. Replacing a door switch is a quick fix that requires only a few simple hand tools and a new switch that costs less than five dollars. To test it simply take a continuity reading through it with the door in the closed position. No continuity indicates a bad switch.

Occasionally the dryer’s electromechanical timers or solid-state controller can cause a failure to start. The dryer will have one or the other located behind the control panel. Electromechanical timers are motor-driven switches that send current to the proper dryer heating element according to the cycle selected. A solid-state controller is a printed circuit board similar to those contained in the back of television sets.

The most common cause of a drum that doesn’t turn is a broken drive belt, although a broken idler pulley could be the cause, as well. The drive belt is similar in design to the serpentine drive belts found under the hood of a modern automobile. The dryer’s drum drive belt runs around the drum, under the idler pulley and around the pulley on the dryer’s drive motor. The spring-loaded idler pulley keeps proper tension on the belt so that there is enough friction between the drive belt and drum to turn the drum with a normal load of clothes in the drum.

If the dryer runs but does not get hot, the problem could be a defective heating element, high temperature cutout thermostat, temperature cycling thermostat thermal overload fuse. The thermostats and thermal fuse are located on top of the heating element enclosure and can be seen as soon as you open the top of the dryer. Thermostats are nothing more than temperature-operated switches. The temperature-cycling thermostat opens and closes repeatedly to keep the drum at the selected temperature. The high-limit thermostat is a safety device that keeps the temperature from reaching dangerously high levels if the temperature-cycling thermostat fails to open properly. The thermal fuse is another safety backup to keep the temperature from rising to a dangerous level if both the cycling thermostat and high limit-thermostat fail. Thermal fuses are not resettable and must be replaced once they open. The heating element itself is enclosed and located behind the drum, but can be tested from the top by using its exposed terminal. Thermostats, thermal fuses and heating elements are all tested by taking a continuity reading through them, but testing the operating temperatures of thermostats takes specialized equipment, so simply replace them if you suspect they are not opening properly.

A dryer that makes a lot of noise or squeaking sounds when operating is indicative of bad bearings. Loud squeaking is usually caused by a worn front-drum support glide. The support glides are rectangular-shaped strips of tough nylon that slip into notches on the front lip of the drum. The glides act as a bearing surface between the front lip of the drum and the lip on the front panel of the dryer that supports the front of the drum. A thumping noise is usually indicative of a bad rear drum-support bearing. These bearings are self-centering bronze bearings located behind the drum that the shaft on the rear of the drum slips into. They are held in place with screws and easily replaced. Replacing the front-support glides or rear-support bearing are really simple, straightforward repairs that almost anyone can do.