The most difficult thing to determine is the cause of the problem when you have a dryer that won’t start. To make this easier, we need to check the parts that might cause this to happen.
Before doing any of the tests with the multi-tester you will need to unplug the dryer.
The door switch indicates if the dryer door is closed or not, a dryer should not start if the door is open. To check the switch, you will to test the continuity between the terminals, this can be done using a multi-tester, when the button is depressed it should read “0” ohms.
The thermal fuse is a heat sensitive fuse that opens and interrupts power if the temperature becomes too hot. This safety device is only found in some dryers to prevent it from overheating. When tested with a multi-meter the fuse should not have any continuity.
Rotary or Push Start Switch
A dryer may have either a rotary or push start switch, usually located on the dryer’s main console. If the dryer doesn’t start when the switch is depressed or turned, the start switch may be defective. The switch can be tested for continuity using a multi-meter.
Defective motor can cause your dryer to not start, sometimes causing a humming loud noise from a bad winding or switch on the motor. Checking the motor should only be performed by a qualified person as the test for this includes dismantling the front panel and doing a live voltage test.
Main Control Board
The main control board is found on electronic controlled dryers, normally located in the dryer’s main control panel. A faulty board might have burnt marks on the surface and/or parts on the circuit and might appear to be shorted out. If found defective, you will probably need to have it replaced.
The timer is also located in the control console of the dryer. The timer contacts control the dryer motor as well as the heat circuit and the timer motor itself. Defective time contacts prevent power from getting to the drive motor; each contact can be checked for continuity with a multi-meter.