Hi James,taken from AD wiring diagram, The ECU has two plugs, A is larger,B is smaller CAS Pin 1 goes to A74,brown/grey = earth Pin 2 goes to A55,black/grey = signal Pin 3 goes to underbonnet fusebox CAM Pin 1 goes to underbonnet fusebox Pin 2 goes to A53,black/violet = signal Pin 3 goes to A72,brown/violet = earth ECU shows 7 earths,A61,A62,A80,A81,B33,B34,B35 all brown Hth Sean