* Under the hood, in the underhood fuse box: This is the most likely location. The fuse box is usually located near the battery, often on the driver's side. The relay itself might be labeled, or you'll need to consult your owner's manual to identify it. The manual will have a diagram of the fuse box showing the location of all relays and fuses.
* Inside the cab, under the dashboard: This is less common but possible. Again, your owner's manual will be essential for locating it if it's inside the cab.
To find it definitively:
1. Consult your owner's manual: This is the best resource. The manual will have a diagram of the fuse box(es) and clearly show the location of the fuel pump relay.
2. Look for a diagram on the fuse box cover itself: Many fuse boxes have a diagram printed on the inside of the cover.
3. Use an online forum or repair manual: Searching online for "2001 GMC Sierra fuel pump relay location" along with your engine size (e.g., 4.8L, 5.3L, 6.0L) might yield helpful results from other Sierra owners. Sites like GM-Trucks.com are good resources.
Important Note: Before working on any electrical components, always disconnect the negative terminal of your battery to prevent accidental short circuits.
