Caprice Wagon V8-350 5.7L (1994)
Shift Interlock: Description and Operation
The Backup Lamp Transmission Position Sensor Switch receives Ignition voltage from I/P Fuse #6 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 Brake Transmission Shift Interlock (BTSI) Solenoid, which is permanently grounded at G200. When the BTSI
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 BTSI Solenoid. This de-energizes the Solenoid, allowing operation
of the Shift Lever.
