I'm asking this question because I am not a professional mechanic. How does the crank position sensor connected to the ignition control unit on MB 500 SEL (1985) ? I have an electrical schematic diagram for this car showing that the two shielded wires from the sensor directed to the test socket, and that is it. I found in my car that is exactly as on diagram (from the sensor to the test socket). So, how the impuls from sensor can reach the ICU? There is a green wire which runs from the distributor to ICU. Is there any galwanic connection between the crank sensor and ICU? And how to check if the sensor is working? Thanks for any explanation. Alexandre.