Our 5 year old series 80 kenmore dryer keeps running through all timer cycles. You have to leave door open or pull the plug to stop it. Is this a major repair or part cost?

Our 5 year old series 80 kenmore dryer keeps running thru all timer cycles. you have to leave door open or pull the plug to stop it. Is this a major repair or part cost?

I have the same problem! Did you get any help on this? My Kenmore finishes the 'timed dry' cycle then moves to the 'air dry' cycle.
What gives?
-David

The timer needs to be replaced. Does anyone knows how to replace it?