1. Identify your engine: Check your vehicle's paperwork (owner's manual, registration) or look for an engine code (e.g., 4.3L, 4.8L, 5.7L, 6.0L, etc.) usually found on a sticker under the hood.
2. Consult a repair manual: Once you know the engine, get a repair manual specific to your year and engine. This is the most reliable way to find the exact location, as diagrams are usually included. You can find these online (e.g., Haynes, Chilton) or at auto parts stores.
3. Search online forums: Search online forums (like GM-Trucks.com or similar) for "2005 GMC Savana [your engine size] fuel filter location." Other owners may have posted pictures or descriptions.
General areas to look (but don't rely on this without verifying with a manual): Fuel filters are often located near the fuel tank, along the frame rail, or sometimes under the vehicle. However, its position can vary greatly depending on the engine and specific van configuration.
Caution: Working with fuel systems can be dangerous. If you're not comfortable working on your vehicle yourself, take it to a qualified mechanic. Fuel is flammable and under pressure.