Car wiring diagrams: Bmw Relay Diagram, wiring diagram, wire wiring harness, schematic circuit diagram, wiring diagran, wireing diagram, wirring diagram, wiring daigram, wiring diagrams. If you like to fix your BMW E electrical issues which normally happen very often and you don't like to visit electricians almost all the time, then.Key to Motronic engine control system wiring diagram picture . Electronic Control Unit ECU . Speed control relay . Temperature switch.BMW Parts for your RRT K Production USA.