You'll need to consult your owner's manual. This is the most reliable way to find the correct fuse location. The manual will have diagrams showing the fuse box layout and identify the fuse specifically for the blower motor.
If you don't have the manual, you can often find a digital copy online by searching "[Your Windstar Year] Ford Windstar Owner's Manual" on Google.
Generally, you'll find the fuse box(es) either under the hood or inside the vehicle, often under the dashboard. Be prepared to look in a few different places and refer to the diagram in your owner's manual.
