The neutral safety switch on a 1984 Ford F-250 is located on the
transmission. More specifically, it's usually 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 (C6, NP435, etc.). You'll likely need to get under the truck to locate it.
Because of its location and the variations in transmission types, a picture or diagram specific to your truck's transmission is helpful for precise identification. A repair manual for your specific year and model F-250 would be the best resource.
