"Ok. Delete the codes in the homelink then try this. (To delete, hold down the first and third buttons at the same time, hold for about 30-60 seconds till the light blinks really fast. Release and check if deleted if the light blinks at a slow but steady pace. That means there's nothing stored on that button)
Hold down the garage door button and the homelink button u want programmed. Once the light changes from a slow blinking light to a rapid blinking light, release both buttons. Then go to the garage door openner and (this is different for all garage door openners) push the "learn" button ONCE. Within 30 secs, press the same button u programmed 3 times, and it should work."