My dryer runs but does not heat up. I bought a thermal switch but cannot find it. Back panel does not remove.

Have to remove the top, swing it back and then remove the front. More complicated than the old remove the back. The thermal switch is on the exhaust tube right after the elements. Suggest you go to You Tube and enter "replacing the thermal switch on a Kenmore dryer". Next time you post, please include the brand.

The safety is behind the drum, but NEVER install a safety without first thoroughly cleaning every part of the dryer. You need to totally tear it down and scrape out and wash all of the parts except the motor, which you vacuum out. You have to totally tear it down piece by piece. Halfway cleaning it will not work because all it takes is one clogged up air passage or dirty sensor. You can go to YouTube to see videos on how to take it apart, but do a very good job or it will fail again quickly. I would get a new belt and change it while you have it apart and get some white lithium grease and grease any bearings you find. The support rollers are greased by pulling the pin and greasing it and greasing the inside of the roller. You need to clean out a drier every two years, at least, according to the manual. You just unplug the wires from the sensors and remove ductwork that they are attached on and clean the entire thing with soap and water. Make sure you go all through the dryer and get all parts like the blower fan and housing (it has to be scrubbed and washed out), vacuum out motor well and clean exhaust. Mark all wires you unplug so you know where they go. If you leave any dirt in the ducts it will blow another fuse quickly or will not maintain the temperature correctly. This is an easier job than you would think. Make sure to clean around all of the sensors, if it has them. Also, change the belt while you have it torn down so you won’t be doing it later. See: Dryer vent cleaning prevents fires - YouTube (http://www.youtube.com/watch?v=A6wmD502-xE) and: Cleaning out a dryer with top lint cleanout - YouTube (http://www.youtube.com/watch?v=OBNDbyRm68M&feature=fvsr)
Cleaning out a dryer: By a woman 2 of 2 - YouTube (http://www.youtube.com/watch?v=a73HTFkcB90&feature=relmfu)
Manuals: https://dl.dropboxusercontent.com/u/8010163/Frigidaire%20Dryers%20Gas%20and%20Electric%20Elect ronic%20Controls%20.pdf
https://dl.dropboxusercontent.com/u/8010163/Frigidaire_27in%20Dryers%20Gas%20and%20Electric%20 Electronic%20Controls.pdf
https://dl.dropboxusercontent.com/u/8010163/Maytag%20Dryers.zip
https://dl.dropboxusercontent.com/u/8010163/Whirlpool%20Dryers.zip