The neutral safety switch, otherwise known as the park/neutral position switch, prevents the vehicle from being started in any position other than PARK and NEUTRAL. It also functions as the back-up lamp switch.
The neutral safely switch is threaded into the transmission case. When the gearshift lever is placed in either the PARK or NEUTRAL position, a cam, which is attached to the transmission throttle lever inside the transmission, contacts the neutral safety switch and provides a ground to complete the starter solenoid circuit. The back-up light switch is incorporated into the neutral safety switch.
The center terminal is for the neutral safety switch and the two outer terminals are for the back-up lights.
There is no adjustment for the switch. If a malfunction occurs, the switch must be removed and replaced.
Removal & Installation
- Raise and safely support the vehicle securely on jackstands.
- Place a drain pan under the switch. A considerable amount of ATF will be lost unless the flow is stopped.
- Label and disconnect the electrical harness.
- Using the proper size wrench, unscrew the switch
- Add the proper amount of ATF. If the flow was not stopped after switch removal, about four quart may have been lost, typically.
- Move the selector lever to the PARK and NEUTRAL positions. Verify that the switch operating lever fingers are centered in the switch opening in the transmission.
- Using a new seal, install the new switch and tighten it to 25 ft. lbs. (34 Nm).
- Test the continuity of the switch, as outlined above.
- Connect the electrical harness.
- Lower the vehicle.
- Disconnect the wiring connector at the switch.
- With an ohmmeter, check for continuity between the center terminal and ground on the transmission case. Continuity should exist only in PARK and NEUTRAL .
- Shift the transmission into REVERSE .
- Check for continuity across the two outer terminals. It should exist only when the transmission is in REVERSE .
- If the switch does not conform to these specifications, check gearshift linkage adjustment to ensure that the switch operating fingers are correctly positioned.