W 150 Pickup V6-239 3.9L (1991)
Neutral Safety Switch: Description and Operation
Transmission Electrical Connections (3 Speed, With Lock-up)
Transmission Electrical Connections (3 Speed, W/O Lock-up)
Transmission Electrical Connections (4 Speed Overdrive)
This switch is located in the housing of the transmission, and sends a signal to the engine controller letting it know if the transmission is in NEUTRAL,
PARK, or a DRIVE GEAR. This input is used to determine fuel injector pulse width, ignition timing advance, and idle speed.