The neutral safety switch on a 2000 Cadillac STS is located on the
transmission. More specifically, it's usually mounted on the
side of the transmission case, near where the shift linkage connects. However, the exact location can vary slightly depending on the transmission type (automatic transmission type).
Because of its location and the need to potentially disconnect linkage, accessing it requires some mechanical aptitude. You'll likely need to get under the car to see it clearly. A repair manual specific to your 2000 Cadillac STS would provide the most accurate location and visual aid.
