Hi. I have tried searching and every guide has not worked so any help would be appreciated. I have a mk3 Mondeo st with one fob and one spare/ transponder key. The battery has gone in the fob. I replaced the battery but it won't do the central locking so I have to unlock with key. I followed all the guides but none worked. If I turn the ignition 1 to 2 r tunes I get the chime. But when I press or hold the unlock button or any button nothing happens. I put a new battery in with the numbers facing up.