I just purchased a 1983 Mercedes 300 D (my very first mercedes), the tach is not working on the car. I did quite a bit of reading on this site and thought I was ready to check it out and repair. Well,when I started to examin I noticed the wire from the sensor going in to the tack amp is pulled out, and the rubber gromet?? is gone. Can any one tell me what color wires attach to pins 7, 8, and 9? If I can attach the wires and the tach works i will need to figure out how to keep the wires in place. Can i purchase the piece of rubber that was holding the wires in place? or do I need to purchase an entire new cable with the rubber piece on it?

thanks

7 is yellow
9 is black
8 is the coax

i used epoxy to keep mine in after the connector disintegrated