Dryer comes on and tumbles. but no heat - Dryers

Hi.

Check the thermal fuse. You can replace the fuse straight away, or you can first test it using a multimeter set on OHMS. If the multimeter reads Ohms infinity when you touch the fuse contacts with its probes, then the fuse is gone.
If the fuse is OK, then you can have a defective thermostat or heating element (electric models), with gas models you test coils, thermostats and ignitor (flame sensor rarely fails).

Regards.

Ginko.