Tachometer 3208 CAT

I took my 4 car carrier to the dealer to get a rebuilt injector pump put in. Before it entered the dealer the tach was working, now, its not. I asked the mechanic why it stopped working and he said by the look of the gauge it never worked. Now im not an idiot i know what a working tach is and whats not. Anyways we know the dealer has to cover themselves with something and i dont feel like argueing with some airhead at a dealer. So the question..........where does the tach get signal from? I know on a gas job it gets it from the dristributor, where does it hook up on a diesel 3208NA cat?

 

Ok so ive went out and found its a cable running from the cam to the cluster, it seperates with a nut in the middleof the cable, i just took it apart and its still greased, im thinking maby its my cluster but i wint know until i get my drill out and spin the cable