According to Sears / re:139.53681B (gray case & blue buttons): Climb up on a ladder, to the door opening unit and remove the cover. Find the "smart" button (it's the only one you can push). Push the smart button and the light will illuminate for 60 - 90 seconds. Descend the ladder within the "illumination window" timeframe. Aim the remote at the unit and push the large button once; the light will flash. If programming two remotes, push the second remote's button immediately after the first. Re-ascend the ladder and replace the cover.
One may purchase a Liftmaster brand remote for a garage door at Sears department stores. They sell complete garage door opener system and replace parts such as the remote for the Liftmaster brand.
One can find more information about Sears Garage Doors from the following sources: Sears Garage Doors, Sears Garage Doors Designer, Sears Home Services, Sears Parts Direct.
There are a variety of places where one can purchase a remote for a garage door. One can find these at stores such as Canadian Tire, Home Depot, Walmart and Sears. These are also available online from sites such as Amazon and eBay.
If it's not too old it will have a yellow, gray, red, or purple button either on the back or the side depending on the model. If it's an older unit it will have dips switches not a button and requires a remote with dip switches as well.
The Chamberlain Group is a manufacturer of garage door openers and associated Chamberlain - the company's do-it-yourself line of garage door openers
Just pull the trigger
A good price for a Sears garage door opener is going to depend on type size garage you have and how much horse power you are looking for. You can get a garage door opener for under $150, but the average price is between $175 and $225.
Alison Becker
If you want to add a remote, press the "set" button on the power unit until the green light blinks, then press the button on the remote. If you want the unit to forget all old codes and accept only the new remote, hold the "set" button until the green light stays on solid, then press the remote button.
The batteries differ with different manufactures. The most common remotes take 2 AA batteries. Others can take up to 3 AAA. The best rule is to open the remote controller and check, so that the replacement batteries are correct.
What's the question?
If the remote is rectangular (approx 1 3/4" X 3") with 1 large button and 2 small round buttons, insert a screwdriver in the slot in the bottom end of the remote at each corner and gently twist. The unit will pop open. Be sure an plase the new battery plus side down.