Please help with stuck tachometer! Yes I've searched!
 

Please read this throughly before attempting to answer my question. Thanks in advance!

Hi all, My lady friend has am automatic 2003 350z hr coupe. Forgive me if I sound dumb I don't know too much about these cars as I have owned and built bmws all my life. Anyways, her tachometer sticks all the time. (WHETHER IT IS SUNNY OR DARK OUT) I have read every single thread on this forum and everyone just blames the sunlight shining on the cluster but gives no real solution on how to solve the problem. In this case the sun is NOT the problem. It happens at night as well. When you smack the top of the cluster the tach sits at the correct rpms for a few seconds then goes back to being stuck anywhere from 2-3000 rpms. Does she need a new cluster? It seems as if there is a loose wire or possibly a bad connection on the stepper motor? Thanks again. I really appreciate any help.

- Jacob

Jacob,

It certainly sound like the gauge itself is at fault. Here's a quick rundown on how the tachometer works. The ECM provide RPM data to the Unified Meter and A/C Amp over the CAN bus. If the ECM data were bad, the engine wouldn't run properly. The signal to the Unified Meter and A/C Amp is a digital word on the bus, not an analog signal. The Unified Meter and A/C amp then sends a separate digital signal to the instrument cluster. This link also includes coolant temperature and fuel level, so if those gauges are working properly the problem is in the tach gauge itself.

To get a more complete understanding of how all the systems in your friend's Z work, I recommend you download the Service Manual for her model year from http://www.nicoclub.com/archives/nis...e-manuals.html.

The stepper motors on these clusters have been known to have issues. You can try testing out your soldering skills and replace the motor. It's a lot cheaper vs. getting a new cluster and having the mileage reprogrammed. The downside is the hassle of dismantling the cluster housing. It's delicate, lots of plastic locking/snap tabs that love to break if you're not careful. If she has an 06+ 350Z, then the paint is also extremely delicate and scratches very easily. Once the housing is broken down, the next hard part is removing the gauge needles and then re-installing them in their correct positions one the motor work is done. I've been through the whole ordeal when I replaced my cluster PCB to get OEM cruise control lights working. It's not easy, but if you're not a perfectionist like I am, then you should do fine.