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

With the ignition in the ON position voltage is supplied to the transmission range switch. When the transmission range switch is in the PARK position voltage is supplied to the automatic transmission shift lock control switch. The normally closed contacts of the automatic transmission shift lock control switch supplies power to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently ground therefore energizes locking the shift lever in the PARK 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 de-energize allowing the shift lever to be moved for the PARK position.