Hi. please excuse my Google Translate English but I speak normally Swedish

it's so that I am in urgent need of a wiring diagram. I have an E 220 CDI which I took the engine out and the entire electrical system. However, I now get nothing will work, especially immobilizer to begin with. if someone has wiring diagram of the immobilizer and the ECU, I would be very grateful. I'm not sure, but it's not that I must have the ignition switch, steering lock and ECU that fit with each other (I have) something else must be wired to get started ECU / engine? are a lot of boxes in a Mercedes