So my tachometer decided to completely quit on me, the needle that is. Everything else still works (Lights, computer, etc.). I do have the dual tach/speedo combo as I have the navigation system installed as well. I decided to buy a Sunpro replacement for the time being until I can afford to get an OEM replacement. This is the one I bought: http://www.sunpro.com/product_detail.php?pid=16327

I've done extensive research to try and find an installation guide for the wiring assignment and came across the OBDII pin assignment (http://www.fes-auto.com/upload/doc/1...er%20Guide.pdf). On the tach itself it has 4 wires: black (ground), red (power), white (lighting), and green (RPM wire).

However, when I spliced each wire with their respective OBDII wire, no luck. The lights, power, nothing worked. When I grounded the tach and attached the white and red directly to battery, though, it lit up and sat to 0 as if it was working. Is my OBDII dead or something? Is the tach not compatible? I own a 05 MCS as well. Thanks in advance!

 

Bump.

 

Wiring it into the OBD connector will not work. The green wire needs to be spliced into the harness running to the ignition coil.
I'm not a big fan of splicing into factory wire harnesses, especially wires that are critical to the operation of the car.
I would suggest looking for a secondhand OEM speedo/tach cluster. Usually, dropping in a secondhand instrument cluster doesn't work with the complicated electronics on these cars. But good news for you, all the complications are in the NAV unit (or the center mount speedo for those without NAV). The aux gauges on the steering column are "dumb" and can be swapped out without any coding or programming.

 

I appreciate the prompt reply! That helps a ton, and I'll be going straight to work as soon as I'm home. The shift light was the only information I could find as far as aftermarket tach-equipment goes, so I figured a shift light would work the same as a tach. I was wrong. Thank you again for shedding some light on the subject. I'll reply again with some feedback and pics of my setup once I'm done.