The circuit on newer cars with
automatic transmissions has a neutral safety, or neutral start switch installed between the ignition switch and the starter. The ignition switch cannot operate the starter motor unless the transmission is in park or neutral.
Late model vehicles with manual transmissions have a starter/clutch interlock switch that requires the clutch to be depressed to the floor.
Neutral Safety Switch
Normal operations of a neutral safety switch provides a quick check for the adjustment of the gear selector linkage.
- To do this, move the selector slowly until it clicks into the PARK position.
- Turn the ignition key to the START position.
- If the starter operates, the PARK position is correct.
- After checking the PARK position, move the lever slowly toward the NEUTRAL position until the lever drops at the end of the NEUTRAL stop in the selector gate.
- If the starter also operates at this point, the gearshift linkage is properly adjusted.
- This quick test also tests the adjustment of the neutral safety switch.
- If the engine does not start in either or both of these positions, the neutral safety switch or the gear selector linkage needs adjustment or repair.
CAUTION
Since you must work under the vehicle to adjust most shift linkages make sure you properly raise and support the vehicle before working under it. Also, wear safety glasses or goggles while working under the vehicle.
A voltmeter can be used to check the switch for voltage when the ignition key is turned to the START position with the shift lever in PARK or NEUTRAL. If there is no voltage, the switch should be adjusted or replaced.
Neutral safety wiring
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