* Under the hood in the fuse box: This is the most common location. The fuse box is usually located under the hood, often near the battery. Look for a diagram on the inside of the fuse box lid showing relay locations. The relay itself might be labeled, or you might have to trace the wires to identify it.
* Inside the car, under the dashboard: Less common, but some models placed relays in a secondary fuse box inside the passenger compartment.
* In the trunk (rare): While less typical for the fuel pump relay, some older vehicles used this placement.
To find it yourself:
1. Consult your owner's manual: This is the best starting point.
2. Locate the fuse box(es): Examine both the under-hood and (if present) under-dash fuse boxes.
3. Look for a relay diagram: The fuse box lid or a sticker inside should have a diagram showing the location and function of relays and fuses.
4. Trace the fuel pump wire: If you can't find it using the diagram, you can try tracing the wire from the fuel pump (located in the fuel tank) to find where it connects to a relay. This is more involved and requires some electrical knowledge. Be careful not to touch anything live.
Safety First: Disconnect the negative battery cable before doing any work near electrical components.
Without knowing the exact engine and trim level of your 1990 Buick LeSabre, it's impossible to give a precise location. Using your owner's manual or a wiring diagram is essential for accurate identification.
