Where is the modulator valve on a 1997 Pontiac Bonneville?

The modulator valve on a 1997 Pontiac Bonneville is part of the transmission itself. It's not a separate, easily accessible external component. You won't find it under the hood or easily reachable anywhere else. To access it, you'd need to remove the transmission.

Therefore, there's no single "location" to point to. A mechanic would need to remove the transmission to service or replace it.