A/T Shift Lock System: System Description

The selector lever cannot be shifted from "P" (Park) unless the brake pedal is applied and the ignition switch is in the "ON" position.
Battery voltage is supplied to the shift lock solenoid by the stop lamp switch.
Ground is supplied to the shift lock solenoid by the park position switch (shift selector).
With the ignition switch "ON", brake pedal applied and the A/T shift selector in "P" (Park), the shift lock solenoid is energized, allowing the selector lever to be shifted from Park.