this procedure worked great for me. I had to do after I replaced the battery. Press both light and enter at the same time.
This is for model 139.53684 security+:
1. with door closed press four numbers for password and then press and HOLD the enter button.
2.press and HOLD the light botton on the door control
3.press and HOLD the door control button
4. after the opener light flashes release all buttons