The fuel pump relay location on a 1990 Corvette is
in the underhood fuse block/relay center. It's not individually labeled "fuel pump relay" like some cars. You'll need to consult your owner's manual or a wiring diagram to identify the correct relay. The diagram will show the relay's position within the fuse/relay center and often indicates its function.
Because there isn't a universally obvious location or label, relying on a wiring diagram specific to the 1990 Corvette is crucial to find it.
