It's crucial to note: Pinpointing the exact location without visual inspection is difficult. A repair manual specific to your 1995 Buick LeSabre will show you exactly where it is located on your particular model. Attempting to find it without a diagram could lead to wasted time and potential damage.
Instead of trying to locate it yourself, consider consulting a repair manual or taking your vehicle to a qualified mechanic for diagnosis and repair if you suspect a problem with the neutral safety switch. This is a relatively simple repair for someone with experience, but not a DIY project for a novice.