Shift Interlock: Description and Operation

Automatic Transmission Shift Lock Control Circuit Description

^ The AT shift lock control requires that the brake pedal be depressed and the ignition switch be placed in the RUN position or the START position before the transmission may be shifted from the PARK position. When the ignition is in the RUN position or the START position, voltage is supplied to the AT shift lock control actuator solenoid through the GAUGES Fuse 9 (10A), circuit 39, the stop lamp/TCC switch, and circuit 1135. When the AT shift lock control actuator solenoid is energized, there is a restrictor arm that holds the shift lever arm in place. When the brake pedal is depressed, the switch within the stop lamp/TCC switch opens cutting off voltage to the AT shift lock control solenoid. When the AT shift lock control actuator solenoid is de-energized, the restrictor arm moves clear of the shift lever arm. This allows movement of the park neutral position switch from the PARK position to any other position.
^ If the vehicle is in the NEUTRAL position, the gear selector will not shift until the brake pedal is depressed. This is similar to the PARK position as described above.
^ In order to override the AT shift lock control, turn the ignition switch to the OFF position. This removes battery voltage from the AT shift lock control actuator solenoid, de-energizing the solenoid and allowing the vehicle to shift.