Where is the egr valve in your 1989 Chevy Caprice?

The EGR valve location on a 1989 Chevy Caprice (assuming the standard 5.0L or 5.7L V8 engine) is on the intake manifold. It's not easily visible without some disassembly. You'll generally find it on the passenger side (right side) of the engine, near the back of the intake manifold. It's usually a small, usually cylindrical or rectangular, component with a vacuum line connected to it.

To find it more precisely: You'll need to consult a repair manual specific to your 1989 Chevy Caprice with the engine size (5.0L or 5.7L). The manual will have diagrams showing the exact location and often a photograph.

Without a diagram, directly looking at it from the top of the engine might be difficult due to other components blocking the view. You may need to remove some parts for better visibility. Be cautious when working on the engine, and remember to disconnect the battery's negative terminal before starting any work.