The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK or NEUTRAL when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consist of the following components:

With the ignition in the ON position, battery positive voltage is supplied to the park/neutral position switch. The switch is closed when the transmission is in the PARK or NEUTRAL position. With the park/neutral position switch closed the circuit continues through the normally-closed automatic transmission shift lock control switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded and therefore energizes locking the transmission shift lever in the PARK or NEUTRAL position. When the driver presses the brake pedal, the contacts in the automatic transmission shift lock control switch open. This causes the automatic transmission shift lock control solenoid to release. This allows the shift lever to move from the PARK position. When the transmission is out of the PARK or Neutral position the automatic transmission shift lock control system is in-active.