To find it, you'll need to:
1. Consult your owner's manual: This is the best starting point. The manual should have a diagram of the fuse and relay boxes showing their locations and what each relay controls.
2. Check the under-hood fuse box: This is the most common location. Look for a diagram on the inside of the fuse box lid. Many relays are interchangeable in appearance, so the diagram is essential.
3. Look for a separate relay center: Some Cadillacs, especially those with more options, had additional relay centers, often located under the dash or in other less obvious locations. Again, a wiring diagram is extremely helpful here.
4. Use a wiring diagram: A wiring diagram for your specific 1983 Cadillac DeVille (including engine type) is invaluable. These are often available online through repair manual websites or forums dedicated to classic Cadillacs.
5. Trace the fuel pump wire: As a last resort, you could trace the wire going to the fuel pump back to its source. This requires some electrical knowledge and patience. Be cautious when working with automotive electrical systems.
Without the specific details of your Cadillac DeVille's engine and options, a precise location cannot be provided. Using the resources listed above will greatly improve your chances of finding the fuel pump relay.
