A bad cycling thermostat could be the reason why your Whirlpool 29 inch electric dryer is not heating properly or not heating at all.
This thermostat is used to control the temperature inside of the tumbler. It is rated at 155 degrees Fahrenheit plus or minus 20 degrees.
This thermostat could be working ok eclectically, but not opening and closing at the proper temperature. If your dryer is not heating at all, you will need a multimeter to check for continuity in the thermostat.
Disconnect the dryer from the wall outlet and remove the back panel. Disconnect the red wire from the thermostat.
Set your multimeter on the lower scale to read ohms. Take a reading between the terminal that you just remove the red wire from and the terminal with the red with a white line on it.
The reading should be close to 0 ohms. That means that the contacts inside of the thermostat are close as they should be. If the reading is infinity, that means that the contacts are open when they should be closed and the thermostat is bad and must be replace.
If the problem is that the temperature inside of the dryer is too high or it is too low and you are sure that the airflow on the dryer is strong, I would replace the cycling or operating thermostat. That way I know that this part is not the problem anymore.
To replace it just remove the holding screw and remove it with all the wires attached to it. Put the new one in place and secure it with the screw. Transfer the wires from the bad part to the new one.
Close the back panel, connect the dryer to the wall outlet and try to see how it works now.
Watch the video below tom see how this repair is done.
Below are the links to the parts needed for this repair.