To find it, you'll likely need to:
1. Consult your owner's manual: This is the best place to start. The manual should have a diagram showing the location of the flasher relay.
2. Look near the fuse box: The flasher relay is often located near the fuse box, usually a black plastic box under the dashboard. Many times this is under the steering column's lower cover.
3. Look for a relay that is roughly square or rectangular: The flasher relay will be similar in size to other relays in the area.
If you can't locate it using these methods, a search on a Cadillac-specific forum or a search on YouTube for "1997 Cadillac Sedan DeVille turn signal flasher location" might yield helpful visual guides. Be cautious when working under the dashboard; disconnecting battery power is a good safety precaution.