How do you reset the door unlock code on my 2005 grand marquis?

To reset the door unlock code on your 2005 Grand Marquis, first, locate the factory code, which is usually found on a label inside the trunk or on the owner’s manual. Enter the factory code using the keypad, then press the "1/2" key within five seconds. You can then enter your new five-digit code, followed by pressing the "1/2" key again to save it. Test the new code by locking and unlocking the doors to ensure it works correctly.