How To Fix A Dryer That Won't Shut Off

The door switch is a safety feature found in all dryers. It is an on and off type switch that prevents the dryer drum from turning when the door is opened. If the dryer continues to tumble after the door is open the problem is most likely the door switch.

How to test your dryer’s door switch with a multi-meter:

1. After unplugging your dryer, locate your door switch. It will be near the door opening.
2. Remove the switch to test it. In some models, you can simply pop it out or remove it with a screw at this stage. In other models, you will need to remove the front panel first.
3. Set your multi-meter to Rx1 and touch the terminals of the switch with the probes. You should receive a reading of infinity. With the probes still touching the terminals, press in on and hold the switch. The reading should change to zero.
4. If your switch fails either of these tests, you need a replacement door switch.

Located in the control console of the dryer the timer consists of a small motor connected to a series of gears that rotate cams, which turn electric contacts off and on inside the timer. The timer contacts control the dryer motor as well as the heat circuit and the timer motor itself. A defective timer motor or a defect in the timer’s electrical contacts can cause the timer motor to fail and the timer will need to be replaced.

How to test a dryer’s timer with a multi-meter:

1. Disconnect your dryer from the power source and remove the control console.
2. Locate and remove your timer. On some models, you will be able to remove it at this stage. In others, you will need to remove the panel behind the control console first in order to remove the switch.
3. After removing the timer, with your multi-meter set to Rx1, touch the probes to the timer’s terminals. You are testing for continuity and should see a reading between 2000 & 3000 ohms.
4. If your test produces a reading outside this range, you need a replacement timer.

On gas and electric dryers that have an "Auto Dry" cycle, the cycling thermostat is often used to advance the timer as well regulate the drum temperature. Essentially, the thermostat will alternately turn on the heat source or the timer motor when the temperature has been satisfied.

How to test the cycling thermostat in a dryer:

1. Unplug your dryer and locate the cycling thermostat. You will need to open the dryer’s cabinet to locate it. It will be found somewhere along the path of air coming from the drum, often on the blower housing.
2. Gently remove your cycling thermostat in order to test it.
3. Set your multi-meter to the Rx1 setting and place the probes onto the thermostat’s terminals. You are testing for continuity and should receive a reading of infinity or zero.
4. If your test produces a reading that is not zero or infinity, you need a replacement cycling thermostat.

Some dryers will use a cool down thermostat to tumble the clothes without heat, at the end of the dry cycle. Power is routed through this thermostat to the drive motor to keep it running until the drum temperature has dropped to a specific temperature. If this thermostat fails it can cause the drum to turn indefinitely or until the door is opened.

How to test a dryer’s cool down thermostat with a multi-meter:

1. Disconnect your dryer from the power source and open the dryer’s cabinet to locate the cool down thermostat. It is usually found near the blower wheel housing.
2. Using pliers to gently grasp the metal connectors and not the wires themselves, remove the cool down thermostat from the dryer.
3. Using a multi-meter on the Rx1 setting, test for continuity by placing the prongs on the thermostat’s terminals. You should see a reading of zero or infinity.
4. If your thermostat produces any other reading, you need a replacement cool down thermostat.