Why is my dryer running cold? While no heating element lasts forever, it isn't always the culprit behind a cold dryer. Most units rely on a safety thermal fuse and a high-limit thermostat to operate; if either fails, your element won't heat at all. Pro Tip: Heat failure is often caused by restricted airflow. To protect your new components, ensure your dryer venting is clear and avoid oversized loads that trap hot air inside the drum. Also ensure that you clean the lint trap with every load.