* Expansion valve (or TXV - Thermostatic Expansion Valve): This is the most likely component you're thinking of. It's located within the HVAC system's housing, usually behind the dashboard. It's not readily accessible without significant disassembly.
* Schrader valves: These are the service ports used to add refrigerant and check pressure. These are usually located on the accumulator/drier (low-pressure side) and the liquid line (high-pressure side). The accumulator/drier is often found near the firewall, but the exact location will depend on the year.
To find the specific location for *your* Chevy Malibu, you'll need to consult a repair manual specific to your vehicle's year and model. A Haynes or Chilton manual, or an online service manual, will provide diagrams and detailed instructions. Trying to locate this without a proper manual could lead to accidental damage.
