To find the correct location for YOUR Grand Caravan ES, you MUST check your owner's manual. The manual will have diagrams showing the location of both fuse boxes and their contents.
Without knowing the year, I cannot give you a precise location. Searching online for "[Your Grand Caravan's Year] Dodge Grand Caravan Fuse Box Location" will likely yield helpful results with diagrams, but the owner's manual is the most reliable source.