Vax Powa 4000 switch wiring diagram?

Hi, Please can anyone help me here?. The switch on my Vax Powa 4000 became detached. I now have a switch which has 1a,2a,3b and 4b terminals on it. The wires that need to connect to it are brown, blue, black and a black/white wire on same connector. Please has anyone a wiring diagram or can tell me which wire goes to which terminal. Thanks in advance