Generally:
* Underhood Fuse Box: This is usually located on the driver's side fender well, often near the battery. It's a larger box and houses higher-amperage fuses.
* Interior Fuse Panel/Block: This is typically located under the dashboard, on the driver's side. It's smaller than the underhood box and contains lower-amperage fuses for interior components. You might need to remove a small panel or access door to see it.
To be absolutely certain: Consult your 1997 Chevrolet Pickup owner's manual. The manual will have diagrams showing the exact locations and fuse layouts for both boxes. You can often find a digital version of the manual online through sites like Helms, Inc. (a common source for GM manuals) or by searching for your specific truck's year, make, and model.