Garage Door Remote and Keypad Programming: what to note first

The new car has three buttons in the mirror for garage doors. You held the old remote up to it as the manual said, the light in the car changed, and yet the door ignores it completely. The handheld remote works fine.

Worth answering before the call

What colour is the small learn or program button under the opener's light cover? Roughly how old is the opener, and can you read its model label? Does the wall button move the door normally right now?

Why does my remote work only when I am right under the door?

Short range is a signal problem, not a pairing problem. LED bulbs in the opener's own sockets can emit radio noise that swamps the receiver, an antenna wire tucked into the housing cannot hear well, and a coin cell near the end of its life transmits weakly before it dies. Swapping the bulb, letting the antenna hang free and fitting a fresh cell usually restore range; if not, the receiver is checked.

How do I program the built-in button in my car?

Often in two steps, on a common HomeLink-style setup. First the car learns a working handheld remote: hold the remote close to the mirror or console and press its button together with the vehicle button until the indicator changes. Then the opener learns the car: press learn on the head unit, walk back to the car within the window that follows, and press the trained button repeatedly until the door responds. Some vehicle systems use a different sequence with no handheld remote, so the vehicle manual is checked first.