As previously stated it's the neutral start switch, located on the driver side of the transmission. Easy DIY replacement if you can get the car raised enough to work underneath. Said switch also operates the reverse lights.

Don't delay getting this addressed. Eventually it will no longer start in N; probably at the most inconvenient time possible. You can still start the car by jumping the starter solenoid to the positive terminal of the battery, but this will annoy your wife...

Part was about $25 when I last purchased one, but that was years ago.

- JimY