Review on Enhanced Motor Products NS267 Neutral/Backup Switch for Better SEO by Paul Rosemark

If your car doesn't even roll over and the battery and starter are fine, that's probably the problem. This switch is also known as the clutch position sensor. This will prevent the vehicle from starting off in gear and lurching forward, which could cause damage or injury to someone or something. A test plug is usually installed next to this switch, which only short-circuits the terminals for test purposes. If the car starts after the terminals are bridged, then the switch is defective. Replace the switch if it is defective as it is a good safety device.