If the vent hose is partially blocked that would cause the auto moisture sensing cycle to run very long as the moisture is pushed through the vent so if the dryer cannot push much moisture through the vent then it will sense that there is too much moisture in the dryer and run very long. make sure the vent is completely clear and also make sure the little flap thing opens and closes correctly where the vent goes outside.

Could not find a wiring diagram for your specific dryer but the following should be close.
http://www.servicematters.com/d...0Sheet%20-%203979710.pdf

Sounds like a problem with the sensor strips, the wire going up to the circuit board or the circuit board itself.

Unplug the unit
Open up the console
Unplug the board
Find the wire that goes down to the sensors. Hopefully the color code will be the same as in the wiring diagram (yellow/red)
Measure it to ground/frame using a high ohms scale.
It should be an open.
Then wet you finger and place it or a wet rag across the sensor strips.
You should now see a resistance.
If not you probably have a connection problem.
If there is now a resistance then the board is probably gone.

Which in my opinion is a rip off as they want around $150.00 for it and all it has is one integrated circuit and a few other components.

FYI: The way this works is that when the clothes are wet the moisture creates a circuit path between the sensor strips. The circuit board senses this and does not allow the timer to advance. When the clothes are dry there is no circuit path created by the moisture so the board then sends power to the timer motor and it advances to the end of cycle.
Your unit thinks the clothes are dry all the time so the timer just runs to the end of cycle.