Tumble dryer spins, but doesn't heat up

You need an ohm meter to do needed checks. Unplug dryer from power,,, then look for sensors and locate the heat coils. Using the ohm meter, check each device by connecting meter to the posts ( your looking for an open curcuit) Note that when you touch the leads of the ohm meter together, the gage will move? This is closed condition, and if the needle did not move, this is called "open". When you find a sensor or heat coil that reads open, that part is bad.
Now make sure there is not a tripped breaker in the fuse panel of the house,,, because even though the dryer is 220 volt,,, 110 volt runs the tumble motor while the other 110 volt curcuit runs the heat side ( so one will work without the other)