In the early to mid 1980s car manufacturers began installing a safety device in all vehicles called a neutral safety switch, which prevents you from starting your vehicle in any gear except for park or neutral. This safety feature came on the heels of numerous cases in which young children left unattended in cars "accidentally" started the vehicles and sent them lurching. The neutral safety switch is mounted on the side of the transmission. Exact locations for your make and model can be determined by accessing either the vehicle owner's manual or from your car's manufacturer.
Jack up your car or truck and set the jack stands in place. Set your vehicle on the jack stands and then push down on the bumper to make sure it is secure. Disconnect the negative battery cable.
Find your neutral safety switch mounted on the side of your car or truck's transmission. It will be the only object protruding from your transmission with a wiring plug attached to it.
Remove the wiring plug from the neutral safety switch by hand and then use the wrench to loosen the switch by turning it to the left.
Screw the new neutral safety switch into your car or truck and tighten it with your wrench. Then plug the wiring harness into your brand new neutral safety switch.
Attach your car or truck's negative battery cable and tighten it down good and then lower your vehicle down from the jack stands.
