Where is the neutral safety switch located on the 2004 ford f150?

The neutral safety switch for the 2004 Ford F-150 is found on the side of the transmission. The switch itself is inside the case and is part of the linkage which allows Your truck to shift gears. It prevents You from starting Your vehicle in any gear other than park or neutral, so it's a good thing from a safety standpoint. If You're having an issue, for example, where You can only start in park but not neutral, before You assume the whole switch is bad, check the electrical connector to it; the metal can start to corrode over time, and removing this corrosion will usually get it back to proper functioning.