Timer does not advance in auto mode

I have a GE dryer that keeps running in auto mode. It still heats but doesn’t stop running. It seems to work ok in the timed mode.
Any suggestions?
Thanks for your help

[SIZE=3]This dryer has two heating elements and if one fails the timer will not advance in auto mode. You will still feel heat because the other element is still working. http://www.appliance-repair-it.com/GE-dryer-timer.html[/SIZE]