The starter in a 1990 Chevy G20 van is located on the
passenger side of the engine, usually towards the
bottom. To be more precise, you'll need to look underneath the vehicle, near the bellhousing (where the engine and transmission connect). It's often partially obscured by components like exhaust manifolds or other engine accessories.
Because of its location, you'll likely need to remove some components to get a good look at, or access to, the starter. A repair manual specific to your year and engine type will be very helpful in providing detailed instructions and diagrams.
