Where is the computer on a 1996 Chevy G20 van?

A 1996 Chevy G20 van doesn't have a computer in the sense of a standalone desktop or laptop. It has an Engine Control Module (ECM), also sometimes called a Powertrain Control Module (PCM), which is a type of onboard computer. This is located somewhere in the engine compartment, often near the firewall or under the hood, but the exact location varies slightly depending on the specific engine and options. It's not easily accessible to the average person and usually requires some mechanical knowledge to locate.