The automatic transmission shift lock control system prevents the automatic transmission from being shifted out of park position unless you depress the brake pedal with the ignition in run or start. When the ignition switch is in run or start, the current flows from the BU/LPS fuse located in the engine wiring harness junction block through CKT 839 (PNK) to the park/neutral position switch. The park/neutral position switch also feeds the backup lamps portion of the switch. With the transmission in park, the current flows to the automatic transmission shift lock control fuse located in the engine wiring harness junction block through CKT 275 (LT GRN). The current then flows to the stoplamp switch through CKT 584 (LT GRN/BLK). The current continues to the automatic transmission shift lock control solenoid through CKT 1135 (DK GRN/WHT). The ground path is provided through CKT 1850 (BLK) to G203. When you depress the brake pedal, the normally closed contacts in the stoplamp switch open and the current flow is interrupted. When the current flow interrupts the automatic transmission shift lock control solenoid de-energizes. The transmission may then shift to another gear. Once the transmission shifts to another gear (except park), the contacts in the park/neutral switch are open thus stopping the current flow to energize the solenoid when the brake pedal releases.