Your dryer's thermal fuse could be malfunctioning and disabling heat when it shouldn't be. The heating element in the dryer might also be damaged in some way. In both of these cases, it's best to ...

For the dryer, you need either gas or — in the US — a special 220 V outlet because the heating elements require a lot of wattage, and doubling the voltage keeps the current levels manageable.

Just hold it up while you clean. Brush and vacuum under the drum and at the top and back of the dryer. Clean thoroughly ...