Where is the fuel cut off switch in a 2000 Chevy Express van?

There isn't a readily accessible, easily identifiable "fuel cut-off switch" like you might find on some equipment in a 2000 Chevy Express van. Fuel delivery is controlled electronically and through the ignition system. Shutting off the ignition is the primary way to cut off fuel.

While there might be a secondary shut-off valve within the fuel system itself (often near the fuel tank), it's not designed for regular use and is usually only accessible after removing some underbody components. Accessing and using it would require mechanical knowledge and isn't a typical method for stopping the van.

In short: Turn the ignition key to the "off" position to stop fuel flow. That's the safest and recommended method. Don't attempt to find or use any hidden fuel shutoff valve unless you're a qualified mechanic performing repairs.