did you try it with some clothes in? these will end the programme without damp washing in? also check two carbon brushes on top of the drum for wear
will try and get some tech info from work tomorrow fault codes etc cannot think off hand matey
a lot of dryers these days sense the moiture in the clothes and turn off when dry to save energy
either put some wet clothes in to try or look to see if there is a timed feature to turn dryer on for 20mins or so this normally does not use sensors so wont switch off