Autolocks are programmable. I do not know if you have a door keypad, so I will give you both procedures:
With Keypad:
1) enter your 5 digit code
2) press and hold 7/8 button
3) while holding the 7/8 button, press the 3/4 button and release it.
4) release the 7/8 button
Success is shown by a short horn beep followed by a longer one.
No keypad:
Make sure all doors are closed.
1) key off
2) key to "run" (dash lights on, not starting)
3) press drivers door "unlock" button 3 times
4) turn key to off position
5) again press drivers door "unlock" button 3 times
6) turn key again to "run" position. HORN WILL CHIRP to confirm programming mode.
7) press the "unlock" button once, followed by the "lock" button once. There should be a short horn chirp and a longer one. This will indicate the autolocks have been "enabled". If there is just a single short chirp, press the "lock" button again to toggle to autolock ON.
8) after the short then long horn chirp, turn key off.
Then verify correct operation.
Good luck!