That switch (detent switch) is self-adjusting. Procedure to reset the point at which the contacts close (and energize the detent solenoid):
1. Remove the switch from the bracket and unplug the connector
2. Locate the spring tab (on the end of the slide closest to the driver)
3. Depress the tab and push the plunger all the way in (towards the firewall)
4. Remount and reconnect the switch
5. Push the gas pedal to the floor (the switch will make a ratcheting sound)
6. That's it - the switch is adjusted.
From the service manual:
