I am attempting to fit an electric PAS pump from a 2001 plate Astra G to my rally car. The pump is fitted to the car and plumbed up but I have a wiring issue. There are 5 wires to the pump - heavy red (presumably live), heavy brown (presumably earth) and 3 light wires, black, brown/white and blue/white. I have tried every combination of connecting the three remaining wires to live/earth and nothing makes the pump spin. Help!