Most modern dryers, while also having a timed dry setting, use a moisture sensor to create a sort of flex dry setting that one can use. Using a moisture sensor, it senses when your clothing is dry enough and ends the cycle instead of just running on a set timed cycle. However, if the moisture sensor no longer works then your clothing may not get dry or the dryer may run indefinitely as it fails to receive the proper signals to stop. However, these are two rather broad and common symptoms. So, if you think it is your moisture sensor that is malfunctioning, here is how you can test it.
First, you want to start with completely dry clothing. When dry clothes are placed in a dryer on a moisture sensor setting, your dryer will run for a few minutes then shut off if the sensor is functioning properly.
However, you will also need to run the opposite test. If the dry clothing test works, you then will want to place damp clothing inside your dryer. When the clothing is damp, your dryer should run until the clothing is dry. If your dryer runs for more than just a few minutes and doesn’t shut off, that means it has passed the test as well.
If your dryer passes both tests, then the dryer sensor is working as intended. The sensor is detecting moisture as intended, but something else is going wrong in the process. However, if your dryer only passes one or none of the tests then you will want to look into replacing the moisture sensor.
Unfortunately, replacing the moisture sensor in most dryers will require a significant amount of disassembly in order to reach, remove, and replace the moisture sensor. Many may feel more comfortable calling a professional appliance repair service to get this done.