Remove the faulty lock by opening the safe door and removing the screws from the mounting bracket with the screwdriver. Gently pick up the lock and disconnect any wire connections from the back of the lock. Completely remove the lock and discard it or save it for repairs or parts.
Pull the loose cables through the exposed spindle hole that was left over after removing the old lock. Pick up the circuit board of the new electronic lock and insert the cables into the inputs on the circuit board. Do not force the cables into the connectors. If they won't fit, try turning the circuit board 180 degrees.
Place the keypad cover over the circuit board. Press the top part of the cover down until you hear a click. Then repeat with the bottom portion of the cover. When the cover is secure, tighten down the provided screw into the hole on the cover with the screwdriver.
Replace the screws on the inside of the door on the mounting plate. You can use the same screws that were installed on the original lock. Tighten each screw down with the screwdriver and attempt to move the lock on the other side of the door. There should be no movement.
Test the lock and ensure it will open the door before you close it. The new lock is connected to the original electrical control unit inside of the safe, meaning you do not need to rewire this device.