Shift Interlock: Description and Operation

The Transmission Position Switch receives Ignition voltage from Fuse 18 in "RUN," "BULB TEST" and "START." When the Transmission Shift Lever is in "PARK," the switch relays voltage to the Brake Light/Cruise Release Switch. The Brake Light/Cruise Release Switch is normally closed, providing voltage to the Shift Inhibit Solenoid, which is permanently grounded at G200. When the Shift Inhibit Solenoid receives voltage, it is energized and prevents the Transmission Shift Lever from being moved out of "PARK." When the Brake Pedal is depressed, the Brake Light/Cruise Release Switch opens, removing voltage from the Shift Inhibit Solenoid. This de-energizes the Solenoid, allowing operation of the Shift Lever.