The 1991 Cadillac DeVille's fuel pump relay isn't a single, easily identifiable component like a fuse. Instead, the fuel pump is controlled by the
Powertrain Control Module (PCM), which is often referred to as the computer. There isn't a dedicated relay in the traditional sense. Any issues with the fuel pump are usually diagnosed by checking the PCM and its associated wiring for problems. A mechanic will use diagnostic tools to test the system.
Therefore, there's no single location to look for a "fuel pump relay" on this model. You'll need to have a professional diagnose the problem rather than trying to locate a non-existent relay.
