Kenmore Dryer "Auto" Cycle trouble

My Kenmore combo washer/dryer is having an issue with the “Auto” drying cycle. In “Auto” mode it runs continuously and the dial doesn’t move. Heats up fine. It works perfect in “timed” mode with the dial moving normally. So I’m guessing it must be some sort of sensor, the “dampness” sensor???. Could it be anything else?

The first thing I would do is clean the vent all the way to the outlet and make sure there is no restrictions.

Gene.