To light up the keypad buttons, press the one-touch locking button when the deadbolt is locked. Pressing the other/numerical buttons will not cause the keypad to light up.
Check that the batteries have power, are inserted correctly into the battery pack, and that the battery pack is inserted correctly. For detailed instructions on how to change the batteries, please see (link to install guide/install video).
If the issue remains, check that the cable between the keypad and the interior is connected with the proper alignment and is completely inserted. For detailed instructions on how to connect the cable, please see (link to install guide/install video?).