How can I fix remote central locking on my 53 reg vauxhall zafira? ?

Hi, I have tried the key in the ignition thing, I have even bought a new board for the key fob! The central locking works but the key fob does not unlock the doors I can use the key in the drivers door but cannot use the buttons on the fob! The fob works as the light comes on when pressed! I have taken it to an auto elec and he said it may need a new module or something but I don't know which module to search for! Does anyone know which fuse is the one for remote central locking? X thanks Maria x