1. Go to the Ford website: https://www.ford.com/
2. Click on the "Owners" tab in the top right corner.
3. Enter your vehicle information (year, make, and model) in the search bar.
4. Click on the "Owner Resources" tab for your specific vehicle.
5. Under the "Documentation" section, you can find the fuse box diagram for your vehicle.
Here is the direct link to the 1999 Ford E-250 fuse box diagram: https://www.fleet.ford.com/resources/ford/general/maintenance/fmvss118e_250.pdf