The part(s) or condition(s) listed below for the symptom Dryer won't start are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The thermal fuse is a safety device designed to protect the dryer from overheating. The fuse is located on the blower housing or at the dryer’s heat source such as the heating element on electric dryers or at the burner on gas models. The fuse should be closed for continuity meaning it has a continuous electrical path through it when good. If overheated the fuse will have no continuity meaning the electrical path is broken and the fuse has blown. A multimeter can be used to test it for continuity. Be aware that a blown thermal fuse is an indication of a restricted exhaust vent from the dryer to the outside. Always check the dryer venting when replacing a blown thermal fuse.
The drive motor turns the drum and the blower wheel to exhaust the air. Before replacing the motor, first check the thermal fuse, start switch, and door switch. If all of these parts are working properly, but the motor is making a humming noise, remove the belt from the motor and check the blower wheel for obstructions. If the blower wheel is clear of obstructions, the dryer motor might be at fault. If you suspect the motor is defective, replace it.
On most dryers, when the dryer belt breaks, the motor will still run, but the drum will not turn. However, some dryers have a switch that shuts off power to the dryer if the drive belt is broken. Check the dryer belt to determine if it is broken. If the belt is broken, replace it.
Dryer drum drive belt. The belt is flat, 92-1/4 inches long, 1/4 inch wide and has 4 ribs and 3 grooves. It replaces many other belts, including some with 5 ribs and 4 grooves. If the drum does not turn, but you can hear the motor running then there is a good chance the belt has broken.
If you have a gas dryer, unplug the dryer from the wall and plug something else into the outlet to determine if the outlet is working. If you have an electric dryer, check the home circuit breaker or fuses. If the circuit breaker or fuses are working, use a multimeter to test the outlet.
The timer might be defective. However, this is very rarely the case. Before replacing the timer, check all the more commonly defective parts. If you determine that all of the other components are working properly, test the timer by using a multimeter and consulting the wiring diagram. If the timer is defective, replace it.