Heater Core
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2008 Suzuki Reno, 2008 Suzuki Forenza, 2007 Suzuki Reno, 2007 Suzuki Forenza, and 2006 Suzuki Reno. However, it is still accessible from the selected car via links, so may be relevant.
The heater core heats the air before it enters the vehicle. Engine coolant is circulated through the core to heat the outside air passing over the fins of the core. The core is functional at all times and may be used to temper conditioned air in the A/C mode as well as in the heat or the vent modes.