If the dryer is heating but not tumbling, this would not be a belt issue because the motor has to be running in order to close the switch contacts that provide power to the heating element. It sounds like the heating element is shorted to ground & took out the thermal fuse that allows power to the motor. First,
unplug the dryer
& remove the rear panel. You will see the heating element mounted on the right hand side. Remove the wires from the element terminals. Remove the element housing support bracket, #4 in the image provided. You can use a small socket set to remove the screw or an extension to reach through the rear part of the cabinet to reach the screw. Lift slightly to dislodge the lower lip of the element housing & pull the complete heater assembly out. Remove the single screw that holds the element in the housing & slide the complete element out. If you find that the element has shorted, donâ€™t forget to replace the thermal fuse along with the element & also be sure the exhaust vent is clear, this could cause the new element to fail prematurely. You can now inspect the heater coils for a short. Another possibility would be a bad motor switch.