Dryer works fine, but timer will not turn off. What is the problem?
Can be a couple of things
Does the machine do this on all cycle?
Does it turn off when you open the door?
Does it turn on when you close the door?
If you unplug it, does it turn on when you plug it in and the timer is set for drying?
I have had success replacing the push to start switch with this problem on these machines, and since it is very inexpensive I would start with that.
If that does not fix it, give us the info asked for above, and we will see what else we can come up with.