A heater core is a small radiator-like device found in vehicles, responsible for providing heat to the cabin. It works by circulating hot coolant from the engine through its core, allowing warm air to flow into the interior when the heater is turned on. This process helps maintain a comfortable temperature inside the vehicle during cold weather. The heater core is typically located behind the dashboard and is connected to the vehicle's cooling system. If it becomes clogged or leaks, it can lead to issues such as reduced heating efficiency or coolant leaks inside the cabin, which may require repairs to the cooling system or dashboard.