You'll need to open the fuse box cover (usually located under the dash on the passenger side) to find the relay. The exact position within that box may vary slightly depending on the specific model (e.g., coupe vs. convertible). Your owner's manual or a wiring diagram specific to your 1993 Corvette would be the best resource to pinpoint its precise location within that fuse box. The relay itself might be labeled, or you could cross-reference it with the diagram using the relay's shape and number of pins.