To be absolutely certain, you should:
* Check your owner's manual: This is the most reliable source.
* Look carefully under the hood: Pay close attention to the area around the battery and any large groupings of wires and fuses. The box might be covered.
* Consult a Ford parts diagram: You can often find these online by searching for "1992 Ford Econoline fuse box diagram" along with your specific model. These diagrams will show the precise location.
Don't hesitate to search online for images of 1992 Ford Econoline engine bays. A visual comparison might help you locate it quickly.