Where is the computer on a Chevy van?

There isn't a computer in a Chevy van in the same way a desktop or laptop computer exists. Chevy vans, like most modern vehicles, have several embedded computers, often called Electronic Control Units (ECUs) or modules. These are distributed throughout the van, controlling various systems like the engine, transmission, airbags, and anti-lock brakes. They're not visible without taking apart parts of the vehicle.