Change keyless entry passcode for chamberlain model 4100 door opener

Without model numbers no one will ever know.

That keypad should work with your opener. I suspect the keypad is bad if you have other remotes that work. If not it could be the logic board.

We have a Chamberlain Whisper Drive Plus. The keyless entry stopped working, suddenly. I have changed the battery, not the problem. I cannot get it to work, and cannot get it to reprogram. The keypad lights up when buttons are pressed, but when I press "Enter" the whole keypad flashes for about 30 seconds and then just goes dark.

I don't know this model. (in australia). the chamberlains here are probably the same. the 4 digit code you first put in the keypad is what you have to use. push the learn button on your operator then punch in your 4 digit No. Hold the enter button on your keypad until the light flashes on the operator.
That should code it in.
freddy51

make sure it is the right keyless entry. For starters, Make sure your antenna hanging off the operator is "purple" color. If it is grey, you have the wrong keyless entry. The keyless you have is for the 315 frequency. If your antenna from the operator is grey, you need to get another keyless entry based on the frequency.

On the back of the motor unit you will find the smart/learn button near where all those white wires go. Press and immediately release it and then walk over to your keypad and key in any 4 digit number you like and press enter. Easy as pie.

First try changing the battery in thh keypad 9V. if that dos not work just moving the wire coming from your opener towards your keypad. DONT CUT THE WIRE OR ADD TO IT. That should take care of it

MOST OF THE WIRELESS KEYPADS YOU DON'T NEED THE OLD CODE TO PROGRAM A NEW ONE.
JUST PRESS THE LEARN/PROGRAM BUTTON AND RELEASE YOU NOW HAVE 20 SECONDS FOR HER TO PUNCH IN THE CODE SHE WANTS AND PRESS AND HOLD ENTER. THE NEXT TIME SHE PRESSES THE BUTTON THE DOOR SHOULD WORK.

NOTE IT WILL WORK FOR ABOUT 20 SECONDS AFTER ENTER IS PRESSED THE FIRST TIME. AFTER THAT YOU NEED TO RE-ENTER THE CODE AND PRESS ENTER.
PROBLEM SOLVED HAPPY NEIGHBOR!!

THE FREQUENCY OF THE UNITS ARE PROBABLY NOT COMPATABLE THEY CHANGED ABOUT 2 YEARS AGO.

SORRY - I THINK YOU NEED A NEW KEYPAD TO GO WITH THE NEW OPENER.

Try: Click on Sears (below FIXYA) on this website, type in your model No & search. You will get a shortlist; click on your model,below the page u will get Manual/Guides. Click on the blue, you have your manual on line.
And dont forget to rate me on this great site.