Product review (5 stars): Saves money
My Whirlpool gas dryer was running but not heating.  I did some research on the net and found out that this is the most common culprit.

Following instructions the instructions I printed I quickly located the thermal fuse.  Tested it with my ohm meter (you can get a decent ohm/volt/amp meter with instructions for about [...], perfect for around the house) and found it defective.  Ordered the new part and installed it.  Put the dryer back together and started it up.

Success, it breathes fire again and I saved myself a bundle of money.  I called a few places and was quoted between $[...] bucks just to come out.  Who knows if they would have found other problems that didn't really exist.