Tachometer Inoperative on a W124
 

I don’t have my own manuals yet so I am using online sources for a 93 300D OM602 engine.

The clock and tachometer are on the same circuit and the clock works and the tachometer does not.

From the schematic the components of the circuit are:
A1p7 (Electronic clock/tachometer)
N6 (A/C Compressor Control Module)
X11/4 (Data Link Connector)
F1 (Fuse box)
X26 (Interior 12 pole connector)

Since the clock works the power is OK. Am I correct to assume that either the signal connector is bad or the tachometer is bad?

Which pin on the connector controls the tachometer signal?

I’ve never had the cluster out of my 300D yet, I’ve only had it one day. But it doesn’t look too hard to remove.

This is the schematic I am using:
http://mb.auto.pl/wis/w124/CD01/ETM/24543002.pdf

Thanks for any advice or suggestions you can give me. :)