Hello friend, I would like to say hello if you have already tried the suiches of the door and they are correct, the most likely thing is that your fault is in the tactile menbrana, this happens due to wear or dirty on the start button, as it is that it is most used, that is why you can to do since all the other keys work is to place an external push-button of only the start button identifies the two start lines and you place the push-button with two cables and ready so you avoid changing all the buttons. Atte Hector of Venezuela