A dryer that heats but does not tumble may have a broken or slipping drum drive belt. This belt wraps around the drum and pulley system to transfer power from the motor. Before replacing it, inspect the idler pulley, motor pulley, and drum rollers for wear or binding. Confirm fit with the complete appliance model because similar belts may...Read more differ in length and rib pattern. Unplug the dryer before opening the cabinet, record the original belt routing, and check that the drum turns smoothly after reassembly.