DavidCamp

I have a quick question. I have a 1985 300SD. Does it have a tachometer sending unit, and where is it located? I see the sensor down at the flywheel and I follow the cable back to the diagnostic plug and the 2 wires (brown & black) disappear under the fuse box. I've been looking on different sites for this, and it keeps showing me a canister-type plug with a series of pins in it. When I unscrew the cap on the diagnostic plug, it's just thta, a cap, without any pics. Thanks for your help.