To check the operation of the neutral safety switch, apply the parking brake and try to start the engine in each position of the selector lever. The engine should start only in Park and Neutral. If it starts in any other position, adjust the shift linkage and retest. If the engine still starts in any position other than Park or Neutral, replace the switch. To replace the switch, disconnect the cable from the negative battery terminal, place the shift lever in Low and apply the parking brake. Raise the vehicle and place it securely on jackstands. Unplug the electrical connector from the neutral safety switch. Carefully unscrew the switch and O-ring. Install the switch and new O-ring, tightening it to the specified torque. Be cautious not to crush or puncture the walls of the switch. Install the electrical connector and connect the negative battery cable. Verify that the engine starts only when the selector is in the Neutral and Park positions. The AODE transmission used on 1992 through 1994 models does not have a neutral safety switch. That function has been incorporated into an information sensor known as the Manual Lever Position (MLP) sensor. And 1995 and later models, which are equipped with a 4R70W transmission, use a transmission range (TR) sensor, a similar device.
