sounds like you need to replace the thermo regulator. It is a small sensor in the bottom of the dryer that shuts it off when it senses its too hot. Find the name and make of the dryer and the model #. Go to your nearest service center and get the part. It is very easy to replace, 2 screws and 2 wires thats it. The service center can pull up a schematic of your dryer and tell you where the part is located. Also clean out the inside of any lint that may of build up!
rich aka mr. fix it, December 2008
