Open the garage door with either a car remote control or the wall push button, if the door is closed. Set up a step ladder under the Craftsman garage door opener so you can reach the power cord.
Pull the end of the power cord out of the ceiling outlet. Follow the wires from each sensor light to the terminals on the door opener. Depending on the model, the terminals are either on the back of the unit or behind the lens cover on the right side. If the terminals are behind the lens cover, squeeze the top and bottom of the cover and rotate the top of the cover down.
Loosen the terminal screws securing the sensor light wires using a Phillips screwdriver, if your model uses screws. Remove the ends of the sensor light wires and retighten the screws. Newer model Craftsman garage door openers use quick-connect terminal. Simply press the tab on the quick-connect terminal with your fingers and pull the sensor wires away from the terminals.
Wrap the ends of the sensor light wires around the hangar bracket of the door opener, if you are not removing the wires at this time. This keeps the ends of the wires from interfering with the operation of the door opener.
Plug the power cord back into the ceiling outlet. Go to the push button on the wall. Press and hold the push button until the door is fully closed.