A neutral safety switch is a device that prevents your vehicle’s engine from starting unless the transmission is in Park or Neutral. The switch is a vehicle safety feature on all vehicles with both automatic and manual transmissions, although the device works a bit differently with each type.
If your engine was able to start with the transmission in gear, your vehicle would move suddenly and unintentionally, making for an extremely dangerous condition. Knowing this, vehicle makers include a neutral safety switch to prevent the engine from starting at all.
In the case of an automatic transmission, the neutral safety switch is usually mounted on the side of the transmission housing. The switch itself is connected to the starter solenoid, breaking the starter electrical circuit anytime the shift lever is out of position (out of Park or Neutral). With a manual transmission, the switch is commonly connected to the clutch pedal assembly. The engine will not start until the clutch pedal is depressed and the transmission is disengaged from the engine.
The process that a technician will use to replace a neutral safety switch depends on whether your vehicle has an automatic or manual transmission. It also depends on the mounting location of the switch.
For a vehicle with a manual transmission, the technician will access the inside of your vehicle on the driver’s side. The switch is mounted on or near the clutch pedal assembly. A wire connector attached to the switch must be disconnected. The switch is detached from its mount and removed from the vehicle. A new switch is installed, and the wire is plugged back into the switch.
The process is a bit more complicated with an automatic transmission. First, the technician must safely lift and support your vehicle in the air for access to the transmission and switch. From there, the following general steps are taken:
