I'm attempting to program a keyless remote entry key fob for a 2005 Ford 500 and have followed the instructions in the owner's manual. The first part of the procedure works as outlined, but when I press the button on the fob nothing happens and the result is that the fob is not programmed. I changed the battery in the fob but the results were the same. Is there something I am missing or that I need to do differently to get the fob programmed?