Where is the fuel cut off switch located on a 1996 Ford F-350 7.3 diesel?

There isn't a readily accessible, single "fuel cutoff switch" like you might find on some gasoline vehicles on a 1996 Ford F-350 7.3L Power Stroke diesel. Fuel delivery is controlled electronically. To stop the engine, you simply turn the ignition key to the "off" position.

While there's no dedicated switch to instantly cut fuel, you could potentially interrupt the fuel supply by disconnecting the fuel lines (extremely messy and potentially dangerous). This is not recommended and is generally only done as a last resort in emergency situations by someone with significant mechanical experience. Doing so can damage fuel system components.

The best and safest way to stop the engine is to use the ignition key.