Hi, I have an euro W123 300D and I want to replace the clock in the instrument panel with tachometer (RPM meter). Is that possible? I have seen that all US W123 300D Turbo have tachometer, so I am going to buy RPM meter from US model. But I don’t know where I have to connect the signal wire. To alternator or...? Actually where the tachometer in US models take the information about engine RPM from?