Where is the location of computer on a 1998 Chevy Astro van?

A 1998 Chevy Astro van doesn't have a computer in the same way a modern car does. It doesn't have a central processing unit (CPU) and motherboard like a desktop or laptop. Instead, it uses various electronic control modules (ECMs), often called computers colloquially, that control different systems. These are distributed throughout the vehicle, not located in a single place. They're usually found under the dashboard, in the engine compartment, or near various components they control (like the transmission). There's no single "computer" location.