When the programming key is presented to the lock, it should begin to flash red and green, indicating that programming mode was initiated. If it does not:
Flashes red only:
Check that the battery is charged.
Solid red:
Lock may have been programmed before. Set back to factory default by taking the following steps:
Take the battery out, hold down the Schlage button, and place the battery back with the button still held down,
The light should flash again. Keep the button held down and wait for it to beep and complete.
Present the programming key again and verify that it now goes to programming mode.