Dryers are pretty simple. You have the drum and drive system, a couple of thermostats(sensors), heating element, blower and timer.
Get your model and serial information and call Jensen Appliance. After giving the the info on the unit tell them exactly what it is doing.
They have diagnosed a fridge, dryer and washer over the phone for me and each time the fix was less than $40.00.

Jensen Appliance www.jensenappliance.com