The turn signal flasher unit in a 1993 Chevrolet Lumina sedan is typically located
under the dashboard, on the driver's side. However, it's *not* always in the same exact spot across all models. It might be behind a panel or near the fuse box. You'll likely need to remove some trim panels to access it.
To be certain, consult a repair manual specific to your 1993 Chevrolet Lumina. A Chilton's or Haynes manual will show you exactly where it is located and provide diagrams to help with removal. Searching online for a wiring diagram for your specific Lumina model year might also help locate it visually.