Greetings,
I have an old Kenmore electric dryer that does not heat properly. In the permanent press cycle (High Heat) the heating element heats up right away and stays hot as the dryer runs, in this cycle the timer dial does not move. I can dry clothes just fine but the dryer will not shut off by itself so I have to watch it. In the "Timed" cycle (High Heat) the dryer works fine, and the timer runs, but the heating element only comes on once in a while if at all (Usually at the end of the 50 minute cycle).
I have tested the heating element and the thermostats with an Ohm meter and everything tests fine. All of these parts have been replaced over the past five years along with the belt, pulley wheels, motor and felt drum seals.
This is rather vexing and I hope someone has some insight to this problem. I could get a new dryer but this one seems to working fine aside from the afore mentioned issues. Thanks, Jack.

Hello,
Sorry, I forgot to mention that I cleaned out all the vent areas. The area inside the back of the drum was very clogged with lint but is now free. All other areas, vents and blower are clean. The puzzling thing for me is that the heater works fine in one cycle but the timer doesn't, and the heater doesn't work in the "Timed" cycle but the timer does. Does this mean a bad control dial? Thanks very much for the help. Jack.