The underhood fuse block is usually located near the battery, often on the driver's side (left side in the US). The relay itself will be a square or rectangular component that can be easily removed and replaced.
To find it without a diagram:
* Check the fuse block diagram: Most fuse blocks have a diagram on the cover showing the location and function of each relay and fuse. Look carefully for a relay associated with the fuel pump, fuel injection, or engine control.
* Use a process of elimination: If the diagram isn't clear, you might try pulling relays one at a time (making note of their positions!) and then trying to start the car. If pulling a certain relay prevents the car from starting, you've likely found the fuel pump relay. *Remember to put the relay back in its original place once you've finished testing.*
Important Note: Always disconnect the negative (-) battery terminal before working on electrical components. This is a crucial safety precaution.
