My dryer will not heat. This is the 3rd time this has happened in the past 2 years. I had a technician fix the problem 2 times but would reallyl like to avoid the cost and repair myself. He said there is a safety switch that will stop the dryer from heating once it reaches a certain temperature. He said that you can fix the problem by simply "flipping a switch". Is this correct? If so do you know where this switch is located?