Lexus GS300 1998 Owner's Manual page 43

KEYS AND DOORS
" 1 Lock
2 Unlock
Push in the lock button to lock and unlock the door.
When locked, the door cannot be opened with either the
outside or inside door handle.
Closing the door with the lock button pushed in will also lock
the door. Be careful not to lock your keys in the vehicle. The
door will not lock if the key is left in the ignition switch when
closing the front doors.
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