To be certain, I recommend:
* Checking your owner's manual: This is the best source of information for your specific vehicle.
* Looking at online forums: Search online forums specific to 1992 Chevy Silverados. Owners often post pictures and descriptions of their relay box locations.
* Visually inspecting your engine bay: Look carefully around the driver's side fender area. The box is usually fairly prominent.
Don't hesitate to look carefully in the surrounding areas, as it could be slightly tucked away or mounted in a slightly different position from other trucks.