First you must reset all the codes in the system... press and hold the outer
two buttons... for about 45 seconds... until the light blink very rapidly.
Then hold your current remote control about 5 inches away from the rearview
mirror... hold both buttons ( your remote and the one on MB) until the light
blinked very rapidly... then release...
If your garage door opener is a rolling code, then you have to press the
learn button on the opener and then press your MB button 3 times.