A model number and/or picture would be very useful!!
Does this dryer have a moisture sensor? If it does, I'd suggest scrubbing the metal sensor strips in the drum with dishsoap and water (don't forget to rinse and dry off!) and see if that helps. Sometimes build-up from liquid fabric softener or dryer sheets can confuse the dryer into thinking the clothes are drier than they really are. Also, I would scrub the lint trap with hot water, dishsoap, and a soft bristle brush to remove any softener buildup that could restrict air flow.