Automatic Transmission Shift Lock Control System

WARNING: This page is about a different car, the 2002 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The automatic transaxle 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 gearshift lever out of the Park position. The system consists of the following components:

The automatic transaxle (A/T) Shift lock control solenoid in the steering column.. Actuator is also known as "A/T shift lock control solenoid".
The automatic transaxle (A/T) shift lock control switch (part of stoplamp switch).

With the ignition switch in the ON position, voltage is supplied to stoplamp switch. Voltage flows through the normally closed contacts of the stoplamp switch to the A/T shift lock actuator. When ground circuit is grounded, this energizes the A/T shift lock actuator causing the transaxle gearshift lever to be physically locked in the Park position. When the brake pedal is pressed the contacts in the stoplamp switch open, de-energizing the A/T shift lock actuator. This allows the gearshift lever to be moved out of the Park position.