Shift Interlock System

With the ignition switch in ON, battery voltage is applied to the shift lock actuator through the METER fuse. Battery voltage is applied at all times through the ROOM fuse to the actuator. Battery voltage through the STOP fuse is applied to the actuator anytime the brake pedal is depressed. With the ignition switch in ON, the brake pedal depressed and the gear selector lever in park, the relays inside the shift lock control actuator energize and apply power and ground to the shift lock servo motor. The motor drives a piston out, which allows the gear selector to be moved out of the park position. When the gear selector is moved out of park, the shift lock control cable mechanically prevents the key from being removed from the ignition switch.

When the vehicle is brought to a stop, the gear selector is put in park and the brake pedal is released, the relays inside the actuator deenergize. Battery voltage from the ROOM fuse is then applied to the shift lock servo motor in the opposite polarity. The motor runs and pulls the piston back in. The gear selector is now locked in the park position until the brake pedal is depressed again. With the gear selector in the park position, the shift lock control cable now allows the key to be removed from the ignition switch. In emergency situations, the selector lever can be moved out of park by mechanical means without the brake pedal being depressed.