The other day I noticed that the load of clothes was taking forever to dry. I opened the dryer door and everything was cool to the touch. I will try to show you how I troubleshot this problem. Hopefully it will be informative. This was a Kenmoor series 90 dryer.
Step 1: Unplug the dryer
First pull the dryer out away from the wall and as with all things electrical, unplug it!
Step 2: Remove the front panel.
Just pull on the front panel, it should just pop off. On the inside of the panel is the electrical schematic. Look it over there are a few things that you want to find, such as the operating thermostat, thermal cutoff, high limit thermostat and the heating element. These should all be in a row wired in series. If any one of these things is bad, then none of it will work.
Step 3: What is inside?
Inside on the right you will notice the heater box. On that heater box is all of the switches and thermostats, with the exception of one, the operting thermostat.
Step 4: Get your meter.
Now take your meter out and set it to Ohms. First test the heater coil. It should read between 7.8 and 11.8 Ohms , mine read 10.2, which means that it is good. If it reads that it is open (my meter reads '1' when it is open) then you need to change the heater element.
Then I checked the next thermostat back, the high limit thermostat. That should be normally closed. So the meter should read that it has continuity. Mine checked out ok.
The next one back, is the thermal cutout switch. this is designed to stop all flow if the temp ever gets above 350 deg F in the heater box. Mine, as you can see in the third picture is bad. Im not sure why it overheated but it will be replaced.