* Under the hood: Engine control module (ECM) would be a major one, handling engine functions.
* Passenger compartment: Possibly behind the dashboard or under the seats, controlling things like climate control, and other interior systems.
* Trunk: Potentially for body control modules or other less frequently accessed systems.
There's no single, easily accessible location for a "computer" as you might think of it in a modern personal computer. It's a network of smaller, specialized computers.