You are right about the keypad being battery operated. The keypad should light up when the first button is pressed and then the numbers will flash when enter is pressed. If a new battery doesn't solve your problem and your other remotes work okay then your keypad has failed.

Thanks don: for the quick reply - I am going to try brand new batteries & hope that's it. If not can you buy just a keypad by itself? at Sears or where?
thank you again.
Bill

Yes you can get just the keypad. Look for the model number on the rear of your keypad and make sure you get one that is the same or compatible. If you can't find that number you can take the model number of the opener itself. It is on the end of the opener closest to the garage door and starts with 139.