Hi all ive just bought a partner van 2015power steering does not work checked fuses checked power to the pump 13volt at the large terminal small plug with 5 wires has 13 v at the blue wire nothing at the other 4can anyone advise how to check ie which wires need to be live with ign on and off chassis number is VF37D9HFOFJ639282 HOPE SOMEONE CAN HELP THANKS