The Brake Transmission Shift Lock is designed to prevent shifting out of PARK while the ignition is ON and the brake pedal is not pressed. The transmission shift lock solenoid is energized only when the ignition switch is in ON or START, the transmission is in PARK, and the brake pedal is not pressed. When the brake pedal is pressed the brake transmission shift lock switch opens and the shift lock soleniod de-energizes. The park/neutral position switch receives ignition voltage from the BTSI BU MiniFuse® #21 through circuit 341. The brake transmission shift Lock switch receives ignition voltage through the park/neutral position switch only when the transmission shift lever is in the PARK position. The brake transmission shift lock switch is part of the brake switch assembly and is normally closed, providing voltage to the brake transmission shift lock control solenoid. The brake transmission shift lock control solenoid locks the shift lever in the PARK position when energized. An open or high resistance in the brake transmission shift lock control solenoid feed or ground circuits will prevent the solenoid from energizing.