High heat stopped, then all heat stopped

Online, I asked an expert who told me to test all parts, but couldn't or wouldn't tell me how to get to those on the back wall. They were impossible to reach to test without removing the drum. On the PartSelect web pages I found the clue: undo two screws that hold the heating element, fuse, and limit thermostat. Pull them forward and you can test them easily. While trying to figure that out and waiting for the expert's reply, I ordered all the possibly failing parts. I tested the new ones and they tested the same as the old, so I decided it was probably the Cycling Thermostat. I replaced that one, put the old set back, and tried it. Voila! It works like a dream. I've sent the unused parts back for reimbursement.