The neutral safety switch on a 1999 Oldsmobile Intrigue 3.8L is located
on the transmission itself. It's not easily accessible without some mechanical knowledge and tools. It's part of the transmission's linkage mechanism and is typically found near where the shift linkage connects to the transmission.
You'll likely need to get underneath the car to see it clearly. A repair manual specific to your 1999 Oldsmobile Intrigue will give you the most precise location and diagrams. Trying to find it without a manual and experience working on cars could be frustrating and potentially damage something.
