When a clothes dryer abruptly stops functioning, the cause can range from a simple power interruption to a complex internal component failure. Before attempting any internal inspection or moving the appliance, disconnect the dryer from its electrical supply at the wall outlet. This systematic approach allows for a safe and logical diagnosis, beginning with external checks and progressing to the machine’s internal mechanics.
Power and Circuit Problems
A dryer that fails to start usually indicates an issue with the electrical supply. Electric dryers require a specialized 240-volt circuit, so a tripped circuit breaker can stop the machine entirely. First, verify that the power cord is securely plugged into the wall receptacle, as dryer vibration can sometimes loosen the connection.
Next, check your home’s electrical panel, as electric dryers use a double-pole circuit breaker. If the breaker is tripped or in the “off” position, resetting it by flipping it fully off and then back on may restore power. If the power supply is verified, check the door switch, which must engage to signal the machine that it is safe to begin the cycle. If the door closes without an audible click, the internal switch may be broken, preventing the unit from starting as a safety precaution.
Mechanical Failures Preventing Tumbling
If the dryer powers on, lights up, and perhaps even hums, but the drum does not rotate, the problem is isolated to the drive system. The most common cause is a broken drive belt, which wraps around the drum, the motor pulley, and the idler pulley. When the belt snaps, the drum is stationary even if the motor runs.
You can check this by manually rotating the drum. If it turns very easily and without resistance, the drive belt is likely broken. The idler pulley assembly maintains tension on the drive belt; if its spring or mounting arm fails, the belt can become slack and slip off the motor pulley. If the drive motor itself seizes or burns out, it is often indicated by a loud humming noise as the motor attempts to start but fails to turn its shaft.
Component Failures Causing No Heat
A dryer that runs and tumbles normally but leaves clothes damp at the end of the cycle has a problem confined to the heating system. In an electric dryer, the heating element is the component responsible for generating the necessary heat. This component is a long, coiled wire made of a resistive alloy, which glows red-hot when 240 volts of electricity are passed through it.
Over time, this element can develop a hairline fracture or break completely, creating an open circuit that prevents the flow of electricity and the production of heat. The cycling thermostat regulates the air temperature inside the drum by switching the heating element on and off. If this thermostat fails, it may remain open, preventing the heating element from receiving power even if the element itself is functional.
The high-limit thermostat is a separate safety device mounted near the heating chamber, designed to trip the circuit if the temperature spikes above a safe threshold. Repeated tripping or a malfunction can cause it to fail in an open position, permanently interrupting power to the heating element. Diagnosing these components often requires internal access and testing for electrical continuity with a multimeter to pinpoint the exact failed part.
Restricted Airflow and Safety Shutoffs
One of the most frequent causes of a dryer stopping or failing to heat is restricted airflow, which triggers a protective safety mechanism. The thermal fuse, a single-use electrical safety device, is designed to interrupt the circuit to the motor or heating element when the internal temperature exceeds its preset limit. This temperature rise is caused by hot, moist air being unable to escape the drum due to an obstruction.
A severely clogged lint screen or an obstructed external vent line prevents the blower fan from effectively exhausting the hot, humid air out of the machine. The trapped heat rapidly increases the internal temperature, causing the thermal fuse to blow, thereby shutting down the dryer to prevent a potential fire hazard. Once the thermal fuse has blown, it cannot be reset and must be replaced, but this replacement will only be temporary if the airflow restriction is not cleared first.
The obstruction can be lint accumulation in the rigid or flexible exhaust duct, a kinked vent hose behind the machine, or debris blocking the vent hood outside the home. Cleaning the entire exhaust path is an important step to ensure proper ventilation and prevent the new thermal fuse from failing immediately. Addressing the airflow problem not only restores the dryer’s function but also maintains the safety of the appliance and the surrounding area.