Digital door locks use a code instead of a physical key to unlock the door. The code is usually four digits. Treat this code with the same respect for security given a key. Obtain the original code when you sign a purchase contract or lease agreement. Change the code as soon as possible.
Remove the door lock by removing the screws holding it from the interior side of the door. Remove the rear plate by turning the lock facedown, compressing the spring-loaded rear plate with your thumb and removing the two, red retaining-screws.
Change the code by changing the position of the red and blue pin tumblers. The red tumblers are in the slots corresponding to the code numbers, and the blue tumblers are in the slots that are not used for the code.
Hold down the "C" button. Remove the red tumbler from the old number and the blue tumbler from the new number; use tweezers for this action. Place the red tumbler in the slot for the new number; the square indent should face the outside of the lock. Place the blue tumbler in the slot for the old number in the same way. Release the "C" button.
Replace the back plate and retaining screws while holding the plate down with your thumb. Test the new code. Press the "C" button, followed by the buttons corresponding to your new lock code. Turn the knob at the base of the lock.
Always press the C button before entering the code. This clears any tumblers that might have been engaged when wrong buttons were pressed on the key pad. Chose a code that's easy for you to remember, but hard for an intruder to guess. The last four digits of your Social Security number make a better code than your street address.
Be careful not to dislodge any of the springs when removing the back plate. This procedure is for most mechanical digital locks; it will not work for electronic digital locks. .