If this is a wireless keypad that is presently working it is easy as 123.

On the back of your motor unit near where all those white wires go you will find a button. Press and immediately release it, walk over to your keypad and key in a 4 digit PIN of your choice and then press enter. Should do it.

I seem to be having problems reprogramming my remotes and wireless keypad. #1, I lost the pin for the keypad. One of the remotes fell, and broke the case. I replaced the broken remote with the same sears# 139.53681B. I also replaced the keypad with the same sears# 139.53684 (black dot). Following all the different programming directions out here, and with the devices, I have had no luck. I can get only one of the remotes working, and never the keypad (either one). I have scoured the internet for additional info, and found none to work. What's my best solution? My opener is a '99 sears# 41A5021-3D, and works great - otherwise.The single button wallmount also works well.

Worked as advertised.